Dermatomyofibroma

Abstract

We report nine examples of a distinct cutaneous plaque-like proliferation of fibroblasts and myofibroblasts. Eight of nine lesions were located in or around the shoulder, including axilla and upper arm. There was a predominance of women to men of 8:1. The lesions measured from 1 to 2 cm in greatest diameter. All patients were young adults (mean age 29.8 yr). All lesions involved the reticular dermis in a plaque-like fashion and extended to the upper part of the subcutaneous septa in seven cases. The lesions consisted of a proliferation of very uniform slender spindle-shaped cells arranged as well-defined elongated and intersecting fascicles with a predominantly parallel arrangement to the skin surface. There was no evidence of cytologic atypia and mitotic figures were infrequent. The spindle-shaped cells were separated by thin collagen fibers. Elastic fibers were preserved and some of them appeared thicker than normal. All adnexal structures were spared. Immunohistochemistry revealed that the cells stained positively for vimentin and muscle actin, but lacked smooth-muscle specific actin, desmin, and S-100 protein. Some dermal dendrocytes stained positively for Factor XIIIa, but the spindle-shaped cells were negative. Electron microscopy studies revealed a mixture of fibroblasts, myofibroblasts, and undifferentiated mesenchymal cells. All lesions were treated by conservative excision; follow-up information revealed no evidence of recurrence. We name this distinct lesion dermatomyofibroma. To the best of our knowledge, this entity has not been previously described in the literature.

Characterization of factor XIIIa+ dendritic cells in dermatofibroma: Immunohistochemical, electron and immunoelectron microscopical observations

“…The cells with 94 Y. Song et al myofilaments resembled to the so-called myofibroblasts [16,17], which have been also reported containing fibronexus-like structures. We could demonstrate that the fibroblastic and histiocytic cells displayed the same basic features; moderate or abundant RER, lipid droplets and/or bundles of myofilaments, in varying proportions.…”

Dermatomyofibroma: Clinicopathologic and Immunohistochemical Analysis of 56 Cases and Reappraisal of a Rare and Distinct Cutaneous Neoplasm

“…3,[5][6][7] Clinically, patients usually present with a longstanding, indurated, plaque-like lesion, and the overlying epidermis can be slightly pigmented. Although most of the cases are small asymptomatic dermal lesions, rare cases may reach a considerable size, [8][9][10] and clinically, a more aggressive dermal neoplasm may be suspected.…”

“…Dermatomyofibroma, first described as a plaque-like dermal fibromatosis, 2 represents a rare but distinct benign dermal proliferation of fibroblasts and myofibroblasts of the skin. 3 We report a series of 56 cases of dermatomyofibroma, discuss histologic and immunohistochemical features, and widen the clinicopathologic spectrum of this entity also in regard to other spindle cell lesions of the dermis and subcutis.…”

Fibromatosis-like myofibroblastic tumour of forearm: Case report and interdisciplinary management

“…Characteristically, the reticular dermis is involved in a plaque-like, diffuse, and acapsular fashion, with extension to the subcutaneous septa in a few cases. They can therefore be confused with a scar or keloid [4,6,7]. They are usually localised in the reticular dermis and always penetrate subcutaneous adipose tissue.…”

“…This is also known as plaque-like dermal fibromatosis, and preferentially occurs in young women, generally located in the upper arm, periaxillary region, and the neck [4,6,7].…”