Rhabdomyosarcoma Arising in a Congenital Melanocytic Nevus

Abstract

A variety of malignancies have been reported to arise within congenital melanocytic nevi, most commonly malignant melanoma, but rarely rhabdomyosarcoma, liposarcoma, and malignant peripheral nerve sheath tumor as well. There have been only three documented cases of rhabdomyosarcoma arising within congenital melanocytic nevi: two embryonal rhabdomyosarcomas and one mixed liposarcoma and rhabdomyosarcoma. One of these cases was also associated with neurocutaneous melanosis. We report a fourth case of rhabdomyosarcoma originating from a congenital melanocytic nevus. A 4-year-old girl presented with a large ulcerated nodule that developed within a hairy congenital nevus on her left gluteal and sacral regions. Her parents refused postoperative adjuvant therapy, and she died 13 months after surgical excision. Histologic sections showed a lesion with two distinct components. There was an expansile proliferation of pleomorphic cells within a fibromyxoid stroma. The neoplastic cells were spindled, and some had abundant eosinophilic globular cytoplasm with occasional cross-striations characteristic of rhabdomyoblasts. They strongly expressed desmin and myoglobin and were negative for S-100 protein and HMB-45. The tumor merged with an adjacent congenital melanocytic nevus characterized by a proliferation of uniform nonatypical melanocytes. The finding of both rhabdomyoblastic and melanocytic differentiation within the same lesion lends support to the hypothesis of their derivation from common pluripotential stem cells or neural crest cells.

Bone marrow metastasis of malignant melanoma in childhood arising within a congenital melanocytic nevus

“…of note, absence of melanin in the cytoplasm of malignant cells in the bone marrow, as was seen in our patient, is also rare and allows an initial consideration of rhabdomyosarcoma. This fact may be important in the differential diagnosis because sporadic cases of rhabdomyosarcoma arising in a congenital melanocytic nevus have been reported 13 . However, immunophenotypic and cytogenetic findings in our patient were consistent with published data on malignant melanoma, including positivity of cd10 and cd117, complex karyotype changes with multiple polysomies reflecting the malignant potential of the tumor, including unbalanced translocations of chromosomes 3, 7, 11, 14 and 16, tetrasomy 20 and gain of chromosome 7 which has been associated with tumor progression 11,[14][15][16][17] .…”

“…laminectomy of l5 and s1 with subtotal resection of a spinal metastasis was required six weeks later due to a neurological impairment including paraparesis and leg pain. after four applications of ipilimumab, active treatment was stopped because of tumor progression and rapid clinical deterioration (anorexia, severe cachexia and poor performance status -lansky score [10][11][12][13][14][15][16][17][18][19][20]. at the parents' request, the therapy was continued with palliative metronomic chemotherapy (vinblastine weekly) plus symptomatic treatment.…”

Malignant transformation in Pre-existing Naevi. A review of two cases

“…11,13,14 Other reported malignancies include liposarcoma, rhabdomyosarcoma, malignant peripheral nerve sheath tumour and neurocutaneous melanosis. 7,11,12,15 Malignant melanoma (MM) is a relatively common neoplasm arising from melanocytes. Its incidence rates show substantial worldwide variations.…”

Neues über kongenitale melanozytäre Nävi

“…Zum Zweiten können auf CMN bereits im Kindesalter Melanome aus tiefer liegenden Vorläuferzellen entstehen. Histologisch handelt es sich dabei um eine dermale oder subkutane knotige Proliferation meist kleiner monomorpher Zellen ("Melanoblastom"; [7,8] domyosarkome, Liposarkome und maligne periphere Nervenscheidentumoren [9]. Es ist aufschlussreich, CMN und assoziierte Neoplasien im Zusammenhang mit weiteren, z. T. wesentlich häufigeren Neurokristopathien wie M. Hirschsprung und Neuroblastom zu betrachten.…”