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Malignant melanoma with a myxoid stroma: A diagnostic pitfall on fine‐needle aspiration biopsy
Author(s) -
Elliott Danielle,
Pitman Martha Bishop
Publication year - 2001
Publication title -
diagnostic cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.417
H-Index - 65
eISSN - 1097-0339
pISSN - 8755-1039
DOI - 10.1002/dc.2034
Subject(s) - medicine , pathology , fine needle aspiration , biopsy , vimentin , nerve sheath neoplasm , stroma , sarcoma , hmb 45 , stromal tumor , s100 protein , cytopathology , malignant peripheral nerve sheath tumor , stromal cell , immunohistochemistry , cytology
Malignant melanoma (MM), both primary and metastatic, may be associated with a prominent myxoid stromal reaction causing diagnostic confusion on fine‐needle aspiration biopsy (FNAB), most often with sarcomas that demonstrate a myxoid stroma, particularly malignant peripheral nerve sheath tumor (MPNST). We present a case of a 32‐yr‐old man with no past medical history who presented with a unilateral neck mass clinically suspicious for lymphoma. FNAB produced a specimen composed of large sheets of anaplastic cells encased in a myxoid stroma that was S100 and vimentin‐positive but HMB‐45‐negative. A diagnosis of MPNST was made. Excision demonstrated a metastatic MM of unknown primary, with a prominent myxoid stromal reaction. A repeat HMB‐45 was again negative. Electron microscopy demonstrated intracytoplasmic melanasomes and cisternae of rough endoplasmic reticulum with intracisternal parallel tubules, confirming the diagnosis. Although HMB‐45 is typically negative in both tumors, S100 should be strongly positive in myxoid MM and only focal in MPNST. Diagn. Cytopathol. 25:185–190, 2001. © 2001 Wiley‐Liss, Inc.