Undifferentiated pleomorphic sarcoma in a child with type 1 neurofibromatosis

Abstract

Conflicts of interest: none declared. Madam, A 10‐year‐old girl without significant past medical history presented with a slightly tender scalp nodule, growing for several months. On examination, there was a 1·5 cm rubbery, mobile, subcutaneous nodule on the left parieto‐occipital scalp. Additionally, she had axillary and inguinal freckling, seven large café‐au‐lait macules (CALMs) ranging in size from 1 to 6·5 cm, and numerous small CALMs less than 1 cm in size. Neurofibromas were not present, and there were no obvious bony abnormalities. Her family history was unremarkable, and she had had a reportedly normal ophthalmological examination at age 6 years. An excision of the scalp lesion was performed. On examination, there was a fragmented, firm tumour with a yellow‐white surface and focal haemorrhage. On cross‐section, the cut surface had a ‘fish flesh‐like’ appearance. Microscopic examination revealed a proliferation of two populations of cells. The first was organized predominantly as storiform fascicles and comprised of cells with plump, spindle‐shaped, hyperchromatic nuclei, and the second was arranged as sheets of cells with enlarged hyperchromatic and pleomorphic nuclei. There were also numerous multinucleated cells, some of which were osteoclast‐like (Figs 1a and 2a). Mitotic figures, some atypical, were readily observed (Fig. 2b). Immunoperoxidase studies revealed that the atypical cells reacted for CD68 (Fig. 1b) but were not reactive for smooth muscle actin, desmin, AE1/AE3, EAB 903 or S100 protein. Following wide local excision, the patient remains disease free to date.