Primary retroperitoneal malignant melanoma: A case report

Abstract

Primary malignant melanoma occurring at an extra cutaneous site is rare. A case of primary malignant melanoma located in the retroperitoneum of an 18-year-old female is presented in this study. Histopathological examination of the tissue biopsies at laparotomy with immunohistochemical stains confirmed a diagnosis of malignant melanoma. Further extensive clinical and radiological investigations proved the retroperitoneum to be the primary site.

Figure 1

(A) Precontrast-enhanced and (B) postcontrast-enhanced CT images show a retroperitoneal mass with heterogeneous enhancement and tortuous blood vessels surrounding it.

Figure 2

(A) H&E, magnification, ×100. (B) H&E, magnification, ×400. A photomicrograph of the operated specimen shows epithelioid neoplastic cells with abundant eosinophilic cytoplasm, round to ovoid nuclei and prominent nucleoli, arranged in a uniform nested to fascicular pattern of growth, separated by vascularized fibrocollagenous septa (white arrow).

Figure 3

Immunohistochemistry of the specimen shows cells staining positive for (A) HMB-45 (magnification, ×400), (B) S-100 (magnification, ×400) and (C) melanin A (magnification, ×400).

Figure 4

(A) Precontrast-enhanced and (B) postcontrast-enhanced CT images, taken 9 months after the patient was discharged, demonstrated a metastatic focus (black arrow).

Figure 5

(A and B) Precontrast-enhanced CT images of different sections and (C and D) corresponding postcontrast-enhanced CT images, taken in February 2008, show the metastasis to have progressed, compared to previous scans.