Histopathological aspects and differential diagnosis of CD8 positive lymphomatoid papulosis

Abstract

Lymphomatoid papulosis (LyP) belongs to CD30+ lymphoproliferative disorders with indolent clinical course. Classic histological subtypes, A, B and C are characterized by the CD4+ phenotype, while CD8+ variants, most commonly classified as type D, were reported in recent years. We present 14 cases of CD8+ LyP. In all patients, self-resolving or treatment-sensitive papules were observed. Of 14 cases 7 produced results with typical microscopic features of LyP type D mimicking primary cutaneous aggressive epidermotropic CD8+ T-cell lymphoma. The infiltration pattern in 4 of 14 cases were consistent with classic LyP type B, without CD30 expression in two cases, resembling mycosis fungoides (MF). The morphology of 2 of 14 cases shared a certain consistency with classic type A and C, lacking eosinophils and neutrophils. Extensive folliculotropism characteristic to type F was observed in 1 of 14 case. Significant MUM1 and PD1 expression were detected in 2 of 14 and 3 of 14 cases, respectively. We concluded that CD8+ LyP may present with different histopathological features compared with type D, similar to CD4+ LyP variants. Differential diagnoses include CD8+ papular MF, folliculotropic MF and anaplastic large cell lymphoma in addition to primary cutaneous aggressive epidermotropic T-cell lymphoma. We emphasise that rare CD8+ LyP cases may exist with CD30-negativity.

CD8‐positive lymphomatoid papulosis (type D): Some lesions may lack CD30 expression and overlap histologically with mycosis fungoides

“…Although not explicitly stated in most previous reports, careful review of previously published images shows that CD30 + epidermotropic cells are also usually limited to the lower half of the epidermis in a significant number of cases . In the three reports where micrographs of CD30− cases were available, the findings were similar to our cases showing prominent epidermotropism of small‐ to medium‐sized cells, an appearance that resembles CD8 + mycosis fungoides, LyP type B, and to a lesser degree the superficial aspect of primary cutaneous aggressive epidermotropic CD8 + T‐cell lymphoma . Epidermal ulceration is also frequently encountered in cases of CD30 + LyP, albeit at a lower frequency than in our cases (37% in one report vs. 60% in our report) …”

“…In one of these two cases (patient 1), gene rearrangement studies were performed and confirmed the presence of the same clone in both specimens. It is worth noting that the clinical outcome of CD8 + LyP has been previously reported to be similar despite the different histopathologic and immunohistochemical features . The current report also provides indirect evidence for that by showing that the same patient can express or lose CD30 at different stages of their disease.…”

“…The histopathologic spectrum of CD8 + LyP is variable and may resemble the different CD4 + subtypes, including A, B, C, E, and “F” subtypes . Although CD30 positivity has been considered a prerequisite for any diagnosis of LyP, there are several reports of CD30‐weak or CD30‐negative cases, especially of the type B (MF‐like) cases .…”

“…proposed the term LyP type D to describe this unusual variant of the disease . Others proposed to limit the use of LyP type D to cases that are histologically indistinguishable from primary cutaneous aggressive epidermotropic CD8 + T‐cell lymphoma, and use LyP type A, B, C, E, “F” and “CD8 variant” for cases that histologically resemble the corresponding subtype of LyP . Despite apparently well‐defined features, CD8 + variants still pose some diagnostic challenges, especially when a detailed clinical description is lacking and/or when classic histologic and immunohistochemical features are altered .…”

“…5 Others proposed to limit the use of LyP type D to cases that are histologically indistinguishable from primary cutaneous aggressive epidermotropic CD8 + T-cell lymphoma, and use LyP type A, B, C, E, "F" and "CD8 variant" for cases that histologically resemble the corresponding subtype of LyP. [6][7][8][9] Despite apparently well-defined features, CD8 + variants still pose some diagnostic challenges, especially when a detailed clinical description is lacking and/or when classic histologic and immunohistochemical features are altered. 10 Of those, loss of CD30 expression is important, particularly as alternative diagnoses including mycosis fungoides and primary cutaneous aggressive epidermotropic CD8 + T-cell lymphoma have greater morbidity.…”