Diagnostic traps awaiting the head/neck pathologist: "Cytoplasm-poor" neoplasms

Abstract

Context: Beyond squamous carcinoma, a variety of diagnostically challenging neoplasms arise within various head and neck sites. This is particularly the situation with neoplasms where little cellular cytoplasm is present to assist the pathologist in categorizing such lesions.

Objective: To highlight diagnostic pitfalls that accompanying neoplasms composed primarily of 'cytoplasmically-poor' cells. These pitfalls include morphologic and immunohistochemical traps that emerge from this class of neoplasms.

Data sources: Selection of pathologic specimens from the author's personal files, and literature review.

Conclusions: Interpretative pitfalls regarding the histopathology and immunophenotype of small 'cytoplasmically-poor' neoplasms are a diagnostic hazard in head and neck surgical pathology practice, and require knowledge of histomorphologic plasticity and aberrant immunophenotyping.

Keywords: Basaloid; Clear cell carcinoma; Malignant melanoma; Olfactory neuroblastoma; Sinonasal undifferentiated carcinoma; Squamous cell carcinoma.