Merkel cell (neuroendocrine) carcinoma of the vulva. A case report with immunohistochemical and ultrastructural findings and review of the literature.
A new case of primary Merkel cell carcinoma (MCC) of the vulva is reported and the literature reviewed for noting its clinical presentation, microscopic, immunohistochemical and ultrastructural features, as well as for establishing the role of immunohistochemistry in the ultimate diagnosis of this uncommon and aggressive tumor. The lesion occurred in a 79 year old patient. Histologically, the tumor was composed of intradermal small cells with high mitotic index and frequent apoptosis. The immunohistochemical study showed positivity for wide spectrum and low molecular weight cytokeratins, epithelial membrane antigen, neurofilaments, neuron specific enolase and chromogranin A. Electron microscopy revealed intermediate filaments in a typical globular paranuclear arrangement. The coexpression of cytokeratins (including cytokeratin 20) and neurofilaments, both in typical globular paranuclear arrangement, made possible the diagnosis of MCC, differentiating it from other malignant small cell tumors such as neuroendocrine metastatic carcinoma.
Departamento de Anatomia Patológica, Facultad de Medicina, Universidad de Málaga and Servicio de Anatomía Patológica, Hospital de Antequera, Spain.
I
I
Hierro
A
A
Blanes
A
A
Matilla
S
S
Muñoz
L
L
Vicioso
F F
FF
Nogales
D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D015266:Carcinoma, Merkel Cell / Q000737:chemistry / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D002479:Inclusion Bodies / Q000648:ultrastructure; D009363:Neoplasm Proteins / Q000032:analysis; D009364:Neoplasm Recurrence, Local; D016900:Neurofilament Proteins / Q000648:ultrastructure; D018714:Radiotherapy, Adjuvant; D014846:Vulvar Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D016900:Neurofilament Proteins