Psammomatous malignant melanoma arising in an intradermal naevus.
OBJECTIVE
A wide variety of differentiation patterns may be found in malignant melanoma. Schwannian features are unusual, and mostly present in the desmoplastic variant. We report the first description of psammoma bodies in malignant melanoma.


RESULTS
A malignant melanoma arose in an intradermal naevus of the scalp in a 51-year-old woman, displaying focal neural-like features in the form of rosette-like pseudo-meissnerian alveolar nests, as well as numerous psammoma bodies grouped in a few areas. Tumour cell immunostaining for S100, HMB45, NKI-C3, and vimentin was detected. In addition, both malignant and benign melanocytic cells showed widespread MART-1 immunoreactivity. Differential diagnosis with psammomatous melanotic schwannoma, a feature of Carney's complex, is particularly emphasized, since dermal variants of this nerve sheath neoplasm have been described. In addition, its potential relationship with cutaneous malignant melanotic neurocristic tumour is discussed.


CONCLUSIONS
This is, to our knowledge, the first reported case of cutaneous malignant melanoma with psammoma bodies.
Monteagudo
C
C
Department of Pathology, Hospital Clínico Universitario, University of Valencia, Valencia, Spain. Carlos.Monteagudo@uv.es
Ferrández
A
A
González-Devesa
M
M
Llombart-Bosch
A
A
D000911:Antibodies, Monoclonal / Q000276:immunology; D000951:Antigens, Neoplasm / Q000032:analysis / Q000276:immunology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D058965:MART-1 Antigen; D008545:Melanoma / Q000276:immunology / Q000473:pathology*; D058950:Melanoma-Specific Antigens; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D018330:Nevus, Intradermal / Q000473:pathology*; D009418:S100 Proteins / Q000032:analysis; D012535:Scalp; D012867:Skin / Q000737:chemistry / Q000473:pathology; D012878:Skin Neoplasms / Q000473:pathology*; D014746:Vimentin / Q000032:analysis
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D058965:MART-1 Antigen; C548667:MLANA protein, human; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D009418:S100 Proteins; D014746:Vimentin