Cutaneous Lipomatous Neurofibroma

Abstract

We report a cutaneous lipomatous neurofibroma on the skin of the left-side parietal area of approximately 9 months' duration in a 67-year-old woman. The regular distribution of adipose tissue throughout the lesion suggested that fat was an integral part of the tumor, not a metaplastic or degenerative process. To our knowledge, this type of lesion has not been documented. The main differential diagnosis embraces neurocristic cutaneous hamartoma, lipoma and its variants, cutaneous meningioma, and neural nevus with fat replacement. We propose that lipomatous neurofibroma of the skin is caused by aberrant development of adipose tissue in a neurofibroma. The lesion originated as pluripotential neural crest cells after migration. This acquired lesion could arise from local stem cells. The old suggestion that neuroectoderm is capable of mesenchymal differentiation may be relevant to the histogenesis of this neoplasm.

Intratumoral Fat in Neurofibroma and Coexistence of Eccrine Hidrocystoma

“…There are several clinical subtypes in neuro- fibroma, such as localized, diffuse, and plexiform variants 1 . Histopathologically, there are several variants including cellular, myxoid, collagenous, hyalinized, epithelioid, pigmented, granular cell, pacinian, atypical, xanthomatized, with epithelial or rhabdomyxomatous differentiation, dendritic cell with pseudorosettes, and lipomatous neurofibroma [2][3][4][10][11][12] . Eccrine hidrocystoma was first described in 1893 by Robinson 13 .…”

“…Second, fatty change in this condition is interesting. Fatty changes have been reported in the normal organ like bone marrow and heart, in the pathologic conditions like fibroepithelial polyp, nevus lipomatous superficialis, neurofibroma and melanocytic nevi, [3][4][5][6][7] and in the peripheral nerve tumors like lipofibromatous hamartoma of the nerve and spinal epidural lipomatosis 8,9 . In recent series, it was reported that lipomatous changes were developed in 6.9% of 320 neurofibromas proposed intradermal nevi with fat increased according to the age of the patient, and Maize and Foster 7 suggested that fat within nevi might be a natural result of aging.…”

“…On histopathologic examination, the lesion is a non-encapsulated dermal or subcutaneous tumor composed of a cellular proliferation within stroma made up of thin, wavy, and faintly eosinophilic fibers 1 . There are several reports about neurofibromas partly replaced by adipose cells [2][3][4] . Fatty changes have been known to be common in some cutaneous lesions, including nevus lipomatous superficialis and intradermal melanocytic nevi [5][6][7] , and several peripheral nerve tumors 8,9 .…”

“…In our case, we found fatty change in neurofibroma and coexistence of eccrine hidrocystoma, and to our knowledge, fatty changes in neurofibroma concurred with eccrine hidrocystoma, have never been documented. The mechanism of intratumoral fat is unclear but several hypotheses have been proposed 3,4 . Here, we report a case of intratumoral fat in neurofibroma and coexistence of eccrine hidrocystoma, and discuss possible pathologic mechanisms of fatty change in our case.…”

Neurofibrolipoma of the dorsum of hand: a case report

“…8 In diffuse lipomatosis, there is diffuse overgrowth of mature adipose tissue affecting large portions of extremity or trunk with no involvement of nerves. 9 There is no standard therapy for neurofibrolipoma.…”