PARALYSIS OF THE SCIATIC NERVE

Summary

The veteran, who served from September 1969 to April 1971, appeals a rating reduction for his service-connected right lower extremity peripheral neuropathy and the denial of service connection for Langerhans cell histiocytosis (LCH). The Board found the rating reduction from 20% to 10% for peripheral neuropathy to be improper, restoring the 20% rating based on the evidence not reflecting an actual improvement in the veteran's ability to function under ordinary conditions. The Board noted that while some sensory involvement improved, the overall impact on functioning did not warrant the reduction, and a 10% rating was insufficient for reduced strength and trophic changes. However, the Board denied an increased rating above 20% for the peripheral neuropathy, finding the evidence did not meet the criteria for a higher evaluation, particularly noting the absence of foot drop and the examiner's clarification that the veteran had weakened flexion/dorsiflexion, not foot drop. For LCH, the veteran sought service connection due to conceded herbicide exposure. The Board denied this claim, noting LCH is not a presumptive condition under 38 C.F.R. § 3.309(e) for herbicide exposure. While acknowledging the possibility of direct service connection, the Board found the probative medical evidence, including a VA examiner's opinion, weighed against a causal relationship, citing a lack of direct evidence linking Agent Orange exposure to LCH and identifying other risk factors like smoking and potential genetic components. The Board found the examiner's opinion, which cited medical literature and the veteran's medical records, to be highly probative.

Rationale

Rating reduction from 20% to 10% was improper; Evidence did not reflect actual improvement in functioning; 10% rating insufficient for reduced strength and trophic changes

Full Decision Text

Citation Nr: A26037896
Decision Date: 04/22/26	Archive Date: 04/22/26

DOCKET NO. 260227-634049
DATE: April 22, 2026

ORDER

The rating reduction from 20 percent to 10 percent for the service-connected right lower extremity peripheral neuropathy, effective February 4, 2026, was improper and restoration of the 20 percent rating is granted.

Entitlement to an increased rating higher than 20 percent for the service-connected right lower extremity peripheral neuropathy is denied.

Entitlement to service connection for Langerhans cell histiocytosis is denied.

FINDINGS OF FACT

1. The evidence does not, overall, reflect an actual improvement in the Veteran's ability to function under ordinary conditions of life and work regarding his service-connected right lower extremity peripheral neuropathy and the rating reduction was not warranted. 

2. The Veteran's service-connected right lower extremity peripheral neuropathy is not manifested by moderately severe symptoms such as motor and/or reflex impairment at a grade reflecting a higher level of limitation or disability or muscle atrophy.

3. The Veteran's Langerhans cell histiocytosis is not related to service, to include toxic exposure risk activities in service. 

CONCLUSIONS OF LAW

1. The rating reduction from 20 percent to 10 percent, effective February 4, 2026, was improper and the criteria for restoration of the 20 percent rating have been met. 38 U.S.C. §§ 1155, 5107;?38 C.F.R. §§?3.105, 3.344.

2. The criteria for an increased rating higher than 20 percent prior to February 4, 2026 for the service-connected right lower extremity peripheral neuropathy have not been met. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.1, 4.3, 4.124a, Diagnostic Code 8520.

3. The criteria for service connection for Langerhans cell histiocytosis have not been met. 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.303.

REASONS AND BASES FOR FINDINGS AND CONCLUSIONS

The Veteran served on active duty from September 1969 to April 1971.

In the February 2026 VA Form 10182, Decision Review Request: Board Appeal (Notice of Disagreement), the Veteran elected the Direct Review docket.

Therefore, the Board may only consider the evidence of record at the time of the February 2026 agency of original jurisdiction (AOJ) decision on appeal. 38 C.F.R. § 20.301. Any evidence submitted after the AOJ decision on appeal cannot be considered by the Board. 38 C.F.R. §§ 20.300, 20.301, 20.801. 

If the Veteran would like VA to consider any evidence that was submitted that the Board could not consider, the Veteran may file a Supplemental Claim (VA Form 20-0995) and submit or identify this evidence. 38 C.F.R. § 3.2501. If the evidence is new and relevant, VA will issue another decision on the claims, considering the new evidence in addition to the evidence previously considered. Id. Specific instructions for filing a Supplemental Claim are included with this decision. 

The Veteran also attempted to appeal his claims for an increased rating for hearing loss and entitlement to a total disability rating based upon individual unemployability (TDIU) in the February 2026 VA Form 10182, citing the February 2026 rating decision. The AOJ did not decide his claims for an increased rating for hearing loss or entitlement to a TDIU in that rating decision. Instead, the AOJ deferred those decisions. Because the AOJ did not adjudicate those claims in the February 2026 rating decision, the VA Form 10182 is not valid as to those attempted appeals. For these reasons, the issues were not docketed. 

The Board notes that an appeal for an increased rating for the left lower extremity peripheral neuropathy was docketed, however, the Board finds that the Veteran did not appeal this issue in the February 2026 VA Form 10182. The Veteran only appealed the rating reduction in the February 2026 rating decision, and the AOJ did not reduce the rating for the left lower extremity peripheral neuropathy in February 2026. Accordingly, the claim for a higher rating for the left lower extremity peripheral neuropathy is not before the Board at this time. The Veteran has one year from the date of the notification letter for the February 
 as to those attempted appeals. For these reasons, the issues were not docketed. 

The Board notes that an appeal for an increased rating for the left lower extremity peripheral neuropathy was docketed, however, the Board finds that the Veteran did not appeal this issue in the February 2026 VA Form 10182. The Veteran only appealed the rating reduction in the February 2026 rating decision, and the AOJ did not reduce the rating for the left lower extremity peripheral neuropathy in February 2026. Accordingly, the claim for a higher rating for the left lower extremity peripheral neuropathy is not before the Board at this time. The Veteran has one year from the date of the notification letter for the February 2026 rating decision to appeal. 

In this matter, the time to change dockets has not expired. See Williams v. McDonough, 37 Vet. App. 305 (2004) ("[T]he Board ordinarily may not decide an appeal before [the time to switch dockets] is up."). In March 2026, the Board sent the Veteran a letter, notifying him of his right to select a different Board review option by submitting a new VA Form 10182 within one year from the date that the AOJ mailed the February 2026 decision on appeal. The Board concludes, however, that the Veteran has implicitly waived his right to change Board dockets under Williams. The present appeal has been advanced on the docket (AOD); therefore, it is not in the Veteran's best interest to further delay this matter.  The Board interprets this AOD status as reflecting an intent to have this matter reviewed in an expeditious manner, which the Board finds to be an implicit waiver of his right to change Board dockets under Williams.

Moreover, in the March 2026 appellate brief to the Board, the Veteran's representative specifically noted that the Veteran has "effectively stated his argument and contentions" and that they are "returning this appeal to the Board for further consideration." The Board interprets the statement to mean that the Veteran's representative believes the appeal is ready for review and adjudication and does not want the Board to wait until the one-year period expires. The combination of the representative's statement and the assignment of AOD status is sufficient for the Board to proceed with an adjudication in this appeal.

Finally, VA regulations provide that, "[u]pon request, a claimant is entitled to a hearing on any issue involved in a claim...before VA issues notice of a decision on an initial or supplemental claim." 38 C.F.R. § 3.103(d)(1). In November 2022, VA amended VA Form 21-526EZ and in May 2024 VA amended VA Form 20-0995 to inform claimants of the right to a hearing at any time during the claims process. The initial claim in this appeal was filed on VA Form 21-526EZ after it was amended; therefore, the Veteran received the requisite notice.

Peripheral Neuropathy Rating Criteria

38 C.F.R. § 4.124a, Diagnostic Code 8520 rates paralysis of the sciatic nerve as follows: moderate incomplete paralysis (20 percent); moderately severe incomplete paralysis (40 percent); severe incomplete paralysis, with marked muscular atrophy (60 percent); and complete paralysis, where the foot dangles and drops, no active movement possible of muscles below the knee, and flexion of knee is weakened or (very rarely) lost. See 38 C.F.R. § 4.124a, Diagnostic Code 8520.

Regulations provide that ratings for peripheral neurological disorders are to be assigned based on the relative impairment of motor function, trophic changes, or sensory disturbance. See 38 C.F.R. § 4.120. Consideration is also given for loss of reflexes, pain, and muscle atrophy. See 38 C.F.R. §§ 4.123, 4.124. The term "incomplete paralysis" indicates a degree of lost or impaired function substantially less than the type picture for complete paralysis given with each nerve, whether due to varied level of the nerve lesion or to partial regeneration. 38 C.F.R. § 4.124a, Note at "Diseases of the Peripheral Nerves." When the involvement is wholly sensory, the rating is for the mild, or at most, the moderate degree. See id. The Note to 38 C.F.R. § 4.124a establishes a maximum disability rating for conditions that are wholly sensory, as opposed to a minimum disability rating for conditions that are more than wholly sensory. See Miller v. Shulkin, 28 Vet. App. 376 (2017).

Neither the Rating Schedule nor the regulations provide definitions for descriptive words such as "mild," "moderate," "moder
 to varied level of the nerve lesion or to partial regeneration. 38 C.F.R. § 4.124a, Note at "Diseases of the Peripheral Nerves." When the involvement is wholly sensory, the rating is for the mild, or at most, the moderate degree. See id. The Note to 38 C.F.R. § 4.124a establishes a maximum disability rating for conditions that are wholly sensory, as opposed to a minimum disability rating for conditions that are more than wholly sensory. See Miller v. Shulkin, 28 Vet. App. 376 (2017).

Neither the Rating Schedule nor the regulations provide definitions for descriptive words such as "mild," "moderate," "moderately severe," and "severe." Spellers v. Wilkie, 30 Vet. App. 211, 219 (2018). Although the Board has at times attempted to define these terms using dictionary definitions, those definitions are problematic because they "do little to explain the Board's understanding of these terms and do not 'disclos[e] that benchmark it employed to reach [its] conclusion.'" Casey v. McDonough, No. 21-7569, slip op. at 3 (Vet. App. Jan. 24, 2023) (mem dec) (Falvey, J.) (quoting Johnson v. Wilkie, 30 Vet. App. 245, 255 (2018)); see also Bethea v. Derwinski, 2 Vet. App. 252, 254 (1992) (single judge decisions may be relied upon for any persuasiveness or reasoning they contain). 

As explained in LeMon v. McDonough, these regulations leave gaps in defining the relevant terms that are filled by VA's Adjudication Manual, M21-1:

The Board "is required to discuss any relevant provisions contained in the M21-1 as part of its duty to provide adequate reasons or bases," Overton, 30 Vet. App. at 264. Clearly relevant to this case are M21-1 provisions regarding evaluations of paralysis of the sciatic nerve. The M21-1 describes mild incomplete paralysis as a disability "limited to sensory deficits that are lower graded, less persistent, or affecting a smaller area." Part V, sbpt. iii, ch. 12, sec. A.2.c. And moderate incomplete paralysis, per the M21-1, should be "reserved for the most significant cases of sensory-only impairment," where the sensory involvement covers "a larger area in the nerve distribution." Id. M21-1 examples of a moderate disability include "motor and/or reflex impairment such as weakness or diminished or hyperactive reflexes (with or without sensory impairment) graded as medically moderate." Id. And the M21-1 provides that a moderately severe evaluation (that is, a 40% rating) is available when there is "[m]otor and/or reflex impairment (for example, weakness or diminished or hyperactive reflexes) at a grade reflecting a higher level of limitation or disability." Id. Atrophy may, but need not, be present for a moderately severe rating.

LeMon v. McDonough, No. 21-3949, 2022 U.S. App. Vet. Claims LEXIS 1998, *7 (Dec. 16, 2022) (mem dec) (Toth, J.). For severe, incomplete paralysis expect motor and/or reflex impairment (for example, atrophy or weakness), trophic changes, and marked muscular atrophy at a grade reflecting a very high level of limitation or disability. See M21-1, Part V, sbpt. iii, ch. 12, sec. A.2.c. 

Ameliorative Effects of Medication

The Board is cognizant of the fact that the Veteran has used medication, including gabapentin, to treat his neuropathy symptoms. The Court has held that in assigning a disability rating, VA may not consider the ameliorative effects of medication where such effects are not explicitly contemplated by the rating criteria. See Jones v. Shinseki, 26 Vet. App. 56 (2012). More recently, the Court stated that the "the Board [is] obligated to discount the beneficial effects of the medication taken for each disability and evaluate the baseline severity of those disabilities" and held that "Jones applies in the evaluation of musculoskeletal disabilities where the relevant [diagnostic code] does not reference medication as a factor in evaluation." Ingram v. Collins, 38 Vet. App. 130 (2025).

The Board notes, however, that neither Jones nor Ingram address how the Board is to discount the beneficial effects of medication. Remanding this appeal to order an addendum medical opinion based on Jones and Ingram, and in the
. See Jones v. Shinseki, 26 Vet. App. 56 (2012). More recently, the Court stated that the "the Board [is] obligated to discount the beneficial effects of the medication taken for each disability and evaluate the baseline severity of those disabilities" and held that "Jones applies in the evaluation of musculoskeletal disabilities where the relevant [diagnostic code] does not reference medication as a factor in evaluation." Ingram v. Collins, 38 Vet. App. 130 (2025).

The Board notes, however, that neither Jones nor Ingram address how the Board is to discount the beneficial effects of medication. Remanding this appeal to order an addendum medical opinion based on Jones and Ingram, and in the lens of the rating criteria under § 4.71a, would almost certainly require an examiner to engage in medical speculation and would result in a medical opinion that lacks the degree of certainty to ascertain, even under the benefit-of-the-doubt standard, the impact of the ameliorative effects of medication on the severity of a veteran's symptoms. See, e.g., Hood v. Shinseki, 23 Vet. App. 295, 298-99 (2005) (medical opinions that are speculative have "little probative value"). Significantly, one of the judges in McCarroll, joined by another judge in concurrence, expressed the same concern as to the implications of the holding in Jones:

The requirement that the Secretary "may not consider the relief afforded by [a veteran's] medication when" applying the rating schedule, as Jones demands, invites medical speculation in trying to guess what a veteran's symptoms might be without the medication, or medical malpractice in the cessation of medication so that the veteran's symptoms without medication might be recorded. The former invites non-helpful guesswork by medical practitioners, and the latter raises, at a minimum, serious ethical concerns that no court should encourage. That Jones essentially requires the Board to consider whether a medical examination is required to determine how serious a veteran's symptoms would have been in an alternate reality in which he or she was not taking his or her required medication should alone demonstrate the fallacy of the Jones holding.

McCarroll v. McDonald, 28 Vet. App. 267, 278 (2016) (internal citations omitted). Because it is highly unlikely that remand to obtain a medical opinion as to the ameliorative effects of medication on the severity of the Veteran's disability would result in a probative, non-speculative opinion as to such, the Board does not wish to further delay adjudication of the Veteran's appeal to engage in likely unfruitful further development pursuant to Jones and Ingram. Moreover, the Board certainly cannot-and will not-order the Veteran to stop taking medication to undergo an examination that would reflect the severity of his disability without the use of pain medication. This would not only be cruel and potentially damaging to the Veteran, but the undersigned finds it would be legally unethical to ask such.

Finally, the Board notes that VA compensation does not contemplate hypothetical symptoms or impairment. Instead, the purpose of VA benefits is to compensate for decreased earning capacity-to compensate for actual symptoms or impairment that an individual experiences in the ordinary conditions of daily life including employment. 38 C.F.R. § 4.10. The Veteran's manifestations of pain have been considered in rating his disability, but it still remains the Board's obligation to rate the condition based on the application of the rating criteria found in the diagnostic codes to the objective medical evidence. 

1. The rating reduction from 20 percent to 10 percent for the service-connected right lower extremity peripheral neuropathy, effective February 4, 2026, was improper and restoration of the 20 percent rating is granted.

2. Entitlement to an increased rating higher than 20 percent for the service-connected right lower extremity peripheral neuropathy is denied.

The Veteran appeals the propriety of the reduction in rating for his service-connected right lower extremity peripheral neuropathy. The threshold issue before the Board is whether the reduction was proper. 

In the February 2026 rating decision, the AOJ decreased the Veteran's disability rating from 20 percent to 10 percent, effective February 4, 2026. Because the reduction in rating did not reduce the Veteran's overall combined rating, which remained 90 percent, the notice provisions of 38 C.F.R. § 3.105(e) do not apply. Therefore, the remaining question is whether the reduction of the disability rating was proper.

The criteria governing rating reductions for service-connected disabilities are found in 38 C.F.R. § 3.344. The provisions of 38 C.F.R. §§ 3.344(a) and (b) apply to ratings that have continued for five years or more. See 38 C.F.R. § 3.344(c). The 
 disability rating from 20 percent to 10 percent, effective February 4, 2026. Because the reduction in rating did not reduce the Veteran's overall combined rating, which remained 90 percent, the notice provisions of 38 C.F.R. § 3.105(e) do not apply. Therefore, the remaining question is whether the reduction of the disability rating was proper.

The criteria governing rating reductions for service-connected disabilities are found in 38 C.F.R. § 3.344. The provisions of 38 C.F.R. §§ 3.344(a) and (b) apply to ratings that have continued for five years or more. See 38 C.F.R. § 3.344(c). The 20 percent rating for the service-connected disability was in effect for a period of less than five years, so the provisions of 38 C.F.R. §§ 3.344(a) and (b) do not apply. See id. Instead, reexamination disclosing improvement will suffice to warrant a rating reduction. See id.

Certain VA regulations, including 38 C.F.R. §§ 4.1, 4.2, and 4.13, apply to all rating reductions, regardless how long the rating has been in effect. See Brown v. Brown, 5 Vet. App. 413, 420-21 (1993). Pursuant to these provisions, the AOJ and the Board "are required in any rating-reduction case to ascertain, based upon review of the entire recorded history of the condition, whether the evidence reflects an actual change in the disability and whether the examination reports reflecting such changed are based upon thorough examinations." Brown, 5 Vet. App. at 421. Further, "in any rating-reduction case not only must it be determined that an improvement in a disability has actually occurred, but also that that improvement actually reflects an improvement in the veteran's ability to function under ordinary conditions of life and work." Id.

The Veteran was awarded a 20 percent rating based on the December 2023 VA examination. Regarding sensory disturbance, light touch/monofilament was decreased in the ankle/lower leg and absent in the foot/toes, position sense was normal, vibration sensation was decreased, and cold sensation was decreased. The Veteran also reported moderate paresthesias and/or dysesthesias and moderate numbness. Regarding impairment of motor functions, the Veteran had 5/5 strength, but he reported difficulty with walking due to foot numbness. Regarding pain, the Veteran reported mild intermittent pain; constant pain was not indicated. 

Regarding loss of reflexes, he had normal reflexes. Regarding trophic changes, there were no trophic changes. Regarding muscle atrophy, there was no muscle atrophy. The examiner diagnosed the Veteran with moderate incomplete paralysis of the right sciatic nerve. 

The Veteran underwent another examination in July 2024. Regarding sensory disturbance, light touch/monofilament was normal, position sense was normal, vibration sensation was decreased, and cold sensation was decreased. The Veteran also reported moderate paresthesias and/or dysesthesias and no numbness. Regarding impairment of motor functions, the Veteran had 5/5 strength, but he reported difficulty with walking due to tingling. Regarding pain, the Veteran reported moderate constant pain. 

Regarding loss of reflexes, he had normal reflexes. Regarding trophic changes, he had slightly red/mottled skin. Regarding muscle atrophy, there was no muscle atrophy. The examiner diagnosed the Veteran with moderate incomplete paralysis of the right sciatic nerve. 

He underwent another examination in November 2024. Regarding sensory disturbance, light touch was normal. The Veteran also reported moderate paresthesias and/or dysesthesias and moderate numbness. Regarding impairment of motor functions, the Veteran had 5/5 strength, his gait was normal, and he denied using an assistive device. Regarding pain, the Veteran reported no constant pain and moderate intermittent pain. 

Regarding loss of reflexes, he had normal reflexes. Regarding trophic changes, he had mild red mottled skin. Regarding muscle atrophy, there was no muscle atrophy. The examiner diagnosed the Veteran with moderate incomplete paralysis of the right sciatic nerve. 

The Veteran's disability rating was decreased based on the February 2026 examination. Regarding sensory disturbance, light touch/monofilament was decreased in the ankle/lower leg and the foot/toes, position sense was normal, vibration sensation was decreased, and cold sensation was decreased. The Veteran also reported mild paresthesias and/or dysesthesias and mild numbness. Regarding impairment of motor functions, the Veteran had 4/5 strength, but he reported difficulty with walking due to numbness and weakness. He denied using an assistive device. Regarding pain, the Veteran
led skin. Regarding muscle atrophy, there was no muscle atrophy. The examiner diagnosed the Veteran with moderate incomplete paralysis of the right sciatic nerve. 

The Veteran's disability rating was decreased based on the February 2026 examination. Regarding sensory disturbance, light touch/monofilament was decreased in the ankle/lower leg and the foot/toes, position sense was normal, vibration sensation was decreased, and cold sensation was decreased. The Veteran also reported mild paresthesias and/or dysesthesias and mild numbness. Regarding impairment of motor functions, the Veteran had 4/5 strength, but he reported difficulty with walking due to numbness and weakness. He denied using an assistive device. Regarding pain, the Veteran reported mild intermittent pain and no constant pain. 

Regarding loss of reflexes, he had normal reflexes. Regarding trophic changes, he had shiny, smooth skin with hair loss. Regarding muscle atrophy, there was no muscle atrophy. The examiner diagnosed the Veteran with mild incomplete paralysis of the right sciatic nerve. 

After reviewing the evidence, the Board finds that the evidence does not, overall, reflect an actual improvement in the Veteran's ability to function under ordinary conditions of life and work. See Brown, 5 Vet. App. at 421. The Board acknowledges that the February 2026 VA examiner indicated that the Veteran's right lower extremity neuropathy was "mild."  The use of terminology such as "mild" by VA examiners, although evidence to be considered by the Board, is not dispositive of the disability's severity. See 38 C.F.R. § 4.2. Instead, it is "the responsibility of the rating specialist to interpret reports of examination in the light of the whole recorded history." Id. The February 2026 examination report shows decreased light touch/monofilament, vibration sensation, and cold sensation, mild paresthesias and/or dysesthesias, mild numbness, intermittent pain, reduced strength, trophic changes, and difficulties ambulating. Thus, while some sensory involvement is improved, the overall impact on his functioning has not. Moreover, a 10 percent rating does not adequately compensate for his reduced strength and trophic changes. 

For these reasons, the Board finds that the rating reduction from 20 percent to 10 percent for the right lower extremity peripheral neuropathy was improper, and restoration of the 20 percent rating is granted.

The Veteran also contended on his VA Form 10182 that his condition worsened, so the Board considered entitlement to a rating higher than 20 percent for the appeal period. The appeal period stems from July 9, 2023, one year prior to the July 9, 2024 VA Form 21-526EZ seeking an increased rating, to February 17, 2026, the rating decision on appeal.

The Board considered the evidence and finds that a 40 percent rating is not warranted. The VA examination reports show normal reflexes, 4/5 to 5/5 muscle strength, and no muscle atrophy. Thus, the evidence does not satisfy nor more closely approximate the criteria for a 40 percent rating for moderately severe incomplete paralysis.  

The Board considered the July 2024 foot conditions examination in which he was diagnosed with foot drop but finds that the diagnosis is outweighed by the other probative medical evidence. Specifically, every peripheral nerves examination report documents 4/5 to 5/5 right lower extremity muscle strength with no evidence of foot drop. His VA and private treatment records do not show foot drop. Critically, the July 2024 VA examiner issued an addendum opinion in September 2024 clarifying that the Veteran does not have foot drop; instead, he has weakened flexion and dorsiflexion which were not options in the peripheral nerves examination reports.  

Accordingly, the Board finds that a rating higher than 20 percent is not warranted for the service-connected right lower extremity peripheral neuropathy, and the claim for an increased rating is denied.

3. Entitlement to service connection for Langerhans cell histiocytosis is denied. 

The Veteran seeks service connection for his Langerhans cell histiocytosis (LCH) as related to herbicide agent exposure.  

His in-service exposure is conceded. Service connection may be granted for specific disabilities associated with exposure to herbicide agents. See 38 C.F.R. § 3.309 (e). LCH is not one of the diseases noted to be associated with exposure to certain herbicide agents under 38 C.F.R. § 3.309(e), however. See 38 U.S.C. § 1116(a); 38 C.F.R. § 3.309(e). 

The Board acknowledges that the Veteran initially claimed service connection for "lung disease" and
osis is denied. 

The Veteran seeks service connection for his Langerhans cell histiocytosis (LCH) as related to herbicide agent exposure.  

His in-service exposure is conceded. Service connection may be granted for specific disabilities associated with exposure to herbicide agents. See 38 C.F.R. § 3.309 (e). LCH is not one of the diseases noted to be associated with exposure to certain herbicide agents under 38 C.F.R. § 3.309(e), however. See 38 U.S.C. § 1116(a); 38 C.F.R. § 3.309(e). 

The Board acknowledges that the Veteran initially claimed service connection for "lung disease" and respiratory cancers are associated with exposure to herbicide agents under 38 C.F.R. § 3.309(e). The probative medical evidence shows, as discussed in more detail below, that his disability does not constitute a respiratory cancer. Instead, it is a clonal hematopoietic neoplasm caused by systemic histiocytosis involving the lungs. 

Nonetheless, service connection may still be awarded based on that exposure on a direct basis. See Combee v. Brown, 34 F.3d 1039, 1043-44 (Fed. Cir. 1994). The three-element test for service connection on a direct basis requires evidence of: (1) a current disability; (2) in-service incurrence or aggravation of a disease or injury; and (3) a causal relationship between the current disability and the in-service disease or injury. Shedden v. Principi, 381 F.3d 1163, 1166 -67 (Fed. Cir. 2004).

The evidence shows a current disability and herbicide agent exposure. See August 2025 VA hematologic and respiratory conditions examination reports and July 2022 VA Herbicide Exposure Verification Memorandum. The remaining question is whether there is a causal relationship between the two. 

In September 2025, a VA examiner opined that the Veteran's LCH was less likely than not due to his toxic risk exposure activities, to include herbicide agent exposure. She asserted that "there is no direct evidence linking agent orange exposure to [LCH]." Instead, "LCH is now recognized as a clonal hematopoietic neoplasm caused by somatic mutations in the MAPK pathway, most notably BRAFV600E mutations" and "there are no peer-reviewed studies within the past decade that have demonstrated a connection between dioxin exposure and LCH development." The examiner noted the Veteran has other risk factors, including being a former smoker and a possible genetic component. 

The Board finds that this medical opinion is highly probative because the examiner provided a rationale supported by the medical literature and treatment record. Specifically, the Veteran's private treatment records show that a pathology revealed a BRAF mutation indicating systemic histiocytosis involving the lungs, and that BRAF mutations or amplification have been reported to result in uncontrolled cell growth and tumorigenesis. His records also show a history of cigarette smoking: a December 2013 VA psychiatric examination report noted that the Veteran had been smoking up to three packs a day and quit 20 years prior, whereas a January 2026 private treatment record noted that he smoked one pack per day for 20 years. 

After reviewing the evidence, the Board finds that service connection is not warranted. There is no evidence linking it to the Veteran's herbicide agent exposure, and the probative medical evidence weighs against service connection. Accordingly, the claim for service connection is denied. 

 

 

Luke Pelican

Acting Veterans Law Judge

Board of Veterans' Appeals

Attorney for the Board	M. Lavan

The Board's decision in this case is binding only with respect to the instant matter decided. This decision is not precedential and does not establish VA policies or interpretations of general applicability. 38 C.F.R. § 20.1303.