Margarida Robalo Cordeiro

Lipomatous neurofibroma associated with segmental neurofibromatosis

To the Editor, Intralesional fat in a neurofibroma has rarely been observed.1– 5 Focal fatty changes in neurofibroma have been ascribed to senescent, metaplasia and chronic injury such as shaving, combing or exposure to ultraviolet radiation.1– 3 Lipomatous neurofibroma is more frequently located on the head and neck of older patients and in long-standing lesions.1– 3 A 71-year-old man presented to our dermatology department with asymptomatic skin lesions distributed on the right forearm with 50 years of duration. He was in good health and no other members of his family exhibited a similar condition. Physical examination showed multiple, soft, dome-shaped, skin-coloured papules and nodules, ranging from 5 to 17 mm in diameter, which were distributed in a linear pattern over the ulnar aspect of the right forearm (Fig. 1). A diagnosis of segmental neurofibromatosis (NF) was made and a skin biopsy disclosed a well-circumscribed, nonencapsulated dermal lesion with normal overlying epidermis composed of loosely spaced spindle cells and wavy collagenous strands in a clear matrix. Focal areas of the lesion were replaced by adipose cells, which appeared with clear round cytoplasmic vacuoles and compressed thin nuclei at the periphery (Fig. 2). The present case of segmental NF showed an unusual histopathological feature in the form of lipomatous neurofibroma, characterized by the presence of well-differentiated adipose tissue embedded in the tumor. Although cutaneous neurofibroma is a common tumor, some pathological variants are rare.1– 4,6 These variants include cellular, myxoid, collagenous, hyalinized, epithelioid, pigmented, granular cell, pacinian, atypical, xanthomatized and lipomatous neurofibroma.2– 4,6 Lipomatous neurofibroma is the latest described variant.1– 3 A recent study showed that the intraneoplastic fat was divided into two groups: focal and diffuse (regularly interspersed).3 Focal fatty change can be a consequence of metaplasia of tumor cells or resident fibroblasts,1– 4 or fatty infiltration from adjacent tissue.2,4 Senescent change or chronic injury in older patients and in long-standing lesions can account for fat deposition (tissue metaplasia).1– 3 However, the diffuse lipomatous neurofibroma represents a distinctive tumor of the peripheral nerve sheath, owing to the differentiation of pluripotential neural crest cells after emigration.2– 5 In our case, the focal presence of

Unilateral progressive osseous heteroplasia

A 50-year-old male patient presented with firm subcutaneous nodules and plaques with a gritty texture, unilaterally affecting the left side of the trunk and the left limbs. These lesions had had a progressive course since early childhood and caused functional impairment. There was no family history of similar disorders. No phospho-calcium metabolism abnormalities were observed. Biopsies of the affected areas demonstrated osteoma cutis. Analysis of DNA showed no mutation of the GNAS gene. The clinical features were consistent with progressive osseous heteroplasia, atypically presented in a unilateral form, probably revealing a mosaic distribution.

Frontal cutaneous meningioma - Case report

Cutaneous meningiomas are rare tumors most commonly located on the scalp. We report the case of a 55-year-old male who presented with a 2x3 cm tumoral lesion on the forehead. The lesion was hard, adherent and covered by normal skin. Incisional biopsy revelead a proliferation of monomorphic round cells, organized in nests and focally forming pseudovascular spaces. Immunohistochemical study revealed positivity for epithelial antigen membrane and vimentin. Vascular markers, cytokeratins and S100 protein were negative. A brain CT scan did not show any evidence of intracranial meningioma. The authors describe the case of a cutaneous frontal meningioma in probable relation with previous cranioencephalic trauma.