Cutaneous or subcutaneous metastasis of non-hematopoietic malignancies in children and adolescents is a rare occurrence but in a high percentage of cases may be the first manifestation of disease. The tumors most likely to metastasize to the skin in children are rhabdomyosarcoma and neuroblastoma and they are more likely than adult malignancies to disseminate to multiple distant sites.

This rare condition illustrates that abnormal cutaneous development may produce fetal hypokinesia, leading to profound effects on intrauterine growth and development. The autosomal recessive pattern of inheritance and morphologic changes of the skin and skeletal system in this disorder suggest that a structural protein or enzyme defect, perhaps of collagen metabolism, may underlie the pathogenesis.

Background: Subcutaneous fat necrosis associated with pancreatic disease is a rare event. The clinical cutaneous findings are non‐specific erythematous nodules with central softening located predominantly on the lower extremities. The histopathologic features of these lesions are very characteristic and diagnostic. Methods: We present an unusual case of pancreatic panniculitis associated with lupus pancreatitis in a 21‐year‐old African American female. The patient presented with lower extremity skin nodules, arthralgia, and serositis prior to the diagnosis of systemic lupus and pancreatitis. The skin lesions progressed despite normalization of serum pancreatic enzymes. Following femoral vein catheterization for renal dialysis, she developed a large indurated area over the left lower quadrant, flank, groin, and upper thigh measuring 25 cm. She was treated with repeated debridement, tissue grafts, and hyperbaric oxygen because of a clinical suspicion of necrotizing fasciitis. Results: Examination of skin biopsies and debrided tissue revealed the pathognomonic features of pancreatic panniculitis without any evidence of necrotizing fasciitis. Organisms were not detected by tissue examination or microbiologic cultures. Conclusions: This case illustrates the potential role of vascular trauma in the pathogenesis of pancreatic panniculitis.

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Malignant peripheral nerve sheath tumor (MPNST) of bone is a rare entity. We have examined three lesions that fit standard histopathologic criteria for MPNST of soft tissues but that arose in the skeleton of three children aged 6 to 13 years. None was affected by neurofibromatosis 1 (NF1). Histologic features typical of MPNST included spindle cells with comma-shaped nuclei, tactoid bodies, nuclear palisading, hyaline bands, and schwannoma-like and curlicue foci. Epithelioid foci were seen in two cases, and heterologous differentiation in one. Immunohistochemistry revealed positivity for S-100 (1 positive/3 tested), vimentin (3/3), glial fibrillary acidic protein (2/3), CD34 (1/1), and CD68 (1/2). Studies for CD99 (0/3), epithelial membrane antigen (0/3), cytokeratin (0/3), CD57 (0/3), and HMB-45 (0/2) were negative. Ultrastructural findings in one of two cases examined included interlacing, attenuated cytoplasmic processes, microtubules, and rare dense-core granules. We conclude that MPNST may arise as a primary bone neoplasm in children without NF1.