Cutaneous epithelioid malignant peripheral nerve sheath tumour: a clinicopathological analysis of 11 cases

Abstract

Cutaneous E-MPNST has the potential to pursue an aggressive clinical course, associated with wide dissemination and unfavourable disease outcome.

Desmoplastic melanoma may mimic a cutaneous peripheral nerve sheath tumor: Report of 3 challenging cases

“…In conclusion, although well documented cases of cutaneous MPNST have been described in the English literature, we cannot at all rule out that some of the cutaneous MPNST could in fact be amelanotic DM. Specifically, the diagnosis of cutaneous MPNST in sun‐damaged skin in the head and neck region from elderly patients, should be made with caution and the exclusion of more common cutaneous tumors, such as DM should be made with care.…”

“…A combination of MITF and S100 positivity is exceptional in epithelioid MPNST, therefore this staining pattern has been regarded as highly specific for melanoma . Similarly, SOX10 IHC expression, which is very frequent in DM is also revealed in MPNST . CD34 expression could favor the possibility of neural tumor instead of DM, although DM can reveal CD34 expression in 7% of the tumors as observed in the early biopsies from case No3 .…”

“…Although initially misdiagnosed, we favored the final diagnosis of DM because both tumors showed the following features: anatomical location in superficial cutaneous sun‐exposed areas, atypical junctional melanocytic hyperplasia, diffuse S100 positivity, tumor cell proliferation in the superficial dermis, the neurotropic component, melanosomes in EM study (in 1 case) and the existence of abundant lymphoid nodules surrounding the tumor cells (second case). In addition, all cases lacked the conventional requirements for the diagnosis of MPNST: tumor relationship with a major nerve or with a neural benign lesion (neurofibroma), or the existence of stigmata suggestive of neurofibromatosis …”

“…sarcomas. [1][2][3][4][5][6][7][8][9] In such cases, MM are usually recognized by the presence of foci with a more conventional appearance and/or the existence of adjacent atypical melanocytic hyperplasia or in situ melanoma. [1][2][3][4] Malignant peripheral nerve sheath tumors (MPNSTs) are problematic to diagnose because of the morphological overlap with other sarcomas and the lack of specific immunohistochemical (IHC) and genetic alterations.…”

“…[5][6][7][8] The cutaneous clinical presentation of MPNST is very unusual and prompted us to excluded other tumors such as MM, spindle cell squamous carcinoma, cutaneous clear cell sarcoma (CCCS), leiomyosarcoma and atypical fibroxanthoma. 1,[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] The most challenging differential diagnosis is between desmoplastic melanoma (DM) and cutaneous MPNST as both neoplasms show S100 positivity (mainly the epithelioid variant of MPNST) and can lack IHC markers of melanocytic differentiation. [4][5][6][7][8][9][10][19][20][21][22][23][24] DM is a rare variant of melanoma, typically arising in chronically sun-damaged skin on the head and neck in elderly patients.…”