To the Editor:
Grayson and Maré1 recently described a unique case of primary cutaneous melanoma with divergent ganglioneuroblastic differentiation. In this report it was stated that there was no evidence of metastatic disease some 30 months after excision of the primary melanoma on the right infrapatellar skin. While this paper was in press, however, the patient presented with uncontrolled local recurrence of the melanoma, and had multiple confluent cutaneous metastases on the right lower thigh. The neoplasm was deemed to be non-resectable, and an above-knee amputation was performed. Gross examination confirmed that there was extensive infiltration into subcutaneous tissue (Fig. 1). Two months later the patient was readmitted to hospital after presenting with nausea, vomiting, dehydration, abdominal pain, a distended abdomen, backache, and weakness of the lower limbs. The patient died a few hours after admission, and an autopsy was requested.
The post-mortem examination was performed by the author. There was subtotal large bowel obstruction related to adhesions that had complicated a total abdominal hysterectomy and bilateral salpingo-oophorectomy performed approximately 15 years previously for endometrial adenocarcinoma. The colon was not gangrenous, and there was no evidence of perforation or peritonitis. The immediate cause of death was diffuse subendocardial infarction, which was probably precipitated by hypovolemia. There was extensive replacement of both lungs and the liver by multiple amelanotic metastases, many of which were necrotic. Metastases were present in multiple thoracic vertebrae, with contiguous infiltration into paravertebral soft tissue and the extradural space around the thoracic spinal cord (Fig. 2). Isolated deposits of metastatic melanoma were also identified in the left atrium, the left ventricular myocardium, bronchopulmonary lymph nodes, the left kidney, and the left adrenal gland. Surprisingly, there were no cerebral metastases.
Histologic examination of the above-knee amputation specimen and all of the metastases sampled at autopsy showed similar features to the previously resected recurrent tumor and the inguinal lymph node metastases. 1 Once again, the neoplasm was composed of pleomorphic amelanotic epithelioid and spindled melanocytes, many of which contained intracytoplasmic rhabdoid inclusions (Fig. 3). Both primary and metastatic melanomas may exhibit a rhabdoid phenotype. 2–4 Interestingly, none of the secondary lesions showed any morphologic evidence of divergent ganglionic, neuromatous and/or neuroblastic differentiation. The divergent ganglioneuroblastic differentiation was encountered exclusively in the initial cutaneous resection specimen, unlike a previously reported case in which ganglioneuroblastic differentiation was only observed in the nodal metastases of the melanoma. 1,5 Whether or not the absence of divergent differentiation in subsequent tissue specimens may have been attributable to prior chemotherapeutic intervention remains speculative. 1
Wayne Grayson, MBChB, PhD, FCPath (SA)
1. Grayson W, Maré LR. Ganglioneuroblastic differentiation in a primary cutaneous malignant melanoma. Am J Dermatopathol. 2003; 25:40–4.
2. Bittesini L, Dei Tos AP, Fletcher CDM. Metastatic malignant melanoma showing a rhabdoid phenotype: further evidence for a non-specific histological pattern. Histopathology. 1992; 20:167–70.
3. Chang ES, Wick MR, Swanson PE, et al. Metastatic malignant melanoma with “rhabdoid” features. Am J Clin Pathol. 1994; 102:426–31.
4. Borek BT, McKee PH, Freeman JH, et al. Primary cutaneous rhabdoid malignant melanoma: a histologic and immunocytochemical study of three cases. Am J Dermatopathol. 1998; 20:123–27.
5. Banerjee SS, Menasce LP, Eyden BP, et al. Malignant melanoma showing ganglioneuroblastic differentiation. Report of a unique case. Am J Surg Pathol. 1999; 23:582–88.