title: Malignant melanocytic neoplasm of pancreas with liver metastasis: Is it malignant melanoma or clear cell sarcoma?
abstract: Malignant melanocytic neoplasm, usually seen in soft tissues, is rare in a visceral location and presents as a diagnostic dilemma. We present a case of pancreatic malignant melanocytic neoplasm with liver metastasis. A 58-year-old man presented with left upper abdominal swelling and loss of appetite. Imaging revealed a large mass arising from the pancreatic tail, and this was diagnosed as malignant neoplasm with melanocytic differentiation on biopsy with the possible differentials of malignant melanoma, clear cell sarcoma (CCS), and perivascular epithelioid cell neoplasm. The patient underwent distal pancreatectomy and splenectomy for the same. Follow-up imaging 6 months later showed a metastatic liver lesion, for which he also underwent a liver resection. BRAF mutational analysis was found to be negative. Both CCS and malignant melanoma have similar morphological features and melanocytic differentiation, but each harbors a distinct genetic background. Differentiation of both has diagnostic and therapeutic implications.
authors.affiliation: Department of General Pathology, Christian Medical College, Vellore, Tamil Nadu, India.
authors.forename: Thomas Alex
authors.initials: TA
authors.lastname: Kodiatte
authors.affiliation: Department of Surgery, Christian Medical College, Vellore, Tamil Nadu, India.
authors.forename: Sam Varghese
authors.initials: SV
authors.lastname: George
authors.affiliation: Department of Medical Oncology, Christian Medical College, Vellore, Tamil Nadu, India.
authors.forename: Raju Titus
authors.initials: RT
authors.lastname: Chacko
authors.affiliation: Department of General Pathology, Christian Medical College, Vellore, Tamil Nadu, India.
authors.forename: Banumathi
authors.initials: B
authors.lastname: Ramakrishna
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D006651:Histocytochemistry; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000473:pathology* / Q000556:secondary* / Q000601:surgery; D058965:MART-1 Antigen / Q000032:analysis; D008297:Male; D008545:Melanoma / Q000175:diagnosis* / Q000473:pathology*; D058950:Melanoma-Specific Antigens / Q000032:analysis; D008853:Microscopy; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000473:pathology; D010180:Pancreatectomy; D010190:Pancreatic Neoplasms / Q000150:complications* / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D011860:Radiography, Abdominal; D009418:S100 Proteins / Q000032:analysis; D018227:Sarcoma, Clear Cell / Q000175:diagnosis / Q000473:pathology; D013156:Splenectomy; D058951:gp100 Melanoma Antigen
chemical_list: D014408:Biomarkers, Tumor; D058965:MART-1 Antigen; D058950:Melanoma-Specific Antigens; C548637:PMEL protein, human; D009418:S100 Proteins; D058951:gp100 Melanoma Antigen