Uncommon Histopathological Variants of Malignant Melanoma: Part 1

Abstract

Despite new horizons opened by recent advances in molecular pathology, histological evaluation still remains the diagnostic gold standard regarding cutaneous melanocytic neoplasms. Several histological variants of melanoma have been described, and their knowledge is crucial for accurate diagnosis and classification of cases with unusual clinicopathological features. Uncommon histological variants of melanoma have been described based on a broad constellation of features, including architectural pattern, stromal alterations, cytological attributes, and other morphological properties. This review is aimed at providing an extensive discussion of unusual but distinctive histopathological variants of melanoma.

Primary cutaneous malignant melanoma in Rett syndrome: Report of a case with nuclear features resembling herpes simplex virus cytopathic effects—a hitherto unrecognized morphological variant

“…It is well known that malignant melanoma has various histopathological morphologies, some more common than others 8‐11 . Our case adds to these morphological variants, where the tumor nuclei display ground glass appearance with chromatin margination, nuclear molding and multinucleation—features that are usually associated with HSV cytopathic effects in keratinocytes.…”

A Wolf in Sheep’s Clothing: Collision of Melanoma and Keratoacanthoma

“…Collision tumors consisting of melanoma and squamous cell carcinoma (called melanocarcinoma in the literature) are very rare, and their biological potential is unknown [ 1 ]. Various theories try to explain their occurrence: as most collision tumors occur on sun-damaged and aged skin, the cancerization theory favors the development of two intermingled neoplasms from two phenotypically distinct clones [ 2 , 3 ]. Paracrine stimulation as a reason for the development of two different malignancies at the same site is discussed, but their simultaneous appearance could also just be a coincidence, as stated by the tumor divergent theory [ 3 , 4 , 5 ].…”

Primary malignant melanoma of the lung: a case report and literature review

“…The prerequisite of the radiologic features includes an abnormal shadow on chest radiography and an irregular mass or node on CT. The prerequisite of pathological diagnosis includes tumour morphology comparable with that of MM, invasion of the bronchial epithelium by melanoma cells, junctional changes including 'dropping off' or 'nesting' beneath the bronchial epithelium, and melanoma often accompanied by complex morphological variations [13], including (1) histological structural variations as typically represented by cell arrangement in a nest, aciniform, trabecular, mamillary, swirling, pseudorosettes, or glomeruli shape;…”