54-year-old with subcutaneous forearm nodule

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54-year-old with subcutaneous forearm nodule

Case # 95-4



History/Physical Findings:

A 54-year-old healthy male presented to a dermatologist with a 2 cm rapidly-growing (first noticed less than a month prior to to presentation) subcutaneous forearm nodule. The nodule was firm and freely mobile and was excised.



A 2.5 x 1.5 x 0.5 cm smooth and largely circumscribed gray to white ovoid mass with fragments of attached adipose tissue. The cut surface was firm and fibrous.

   fasc1 fasc2

Figure 1 (low power): There is a well-circumscribed nodule composed of spindled cells within a collagenous and myxoid matrix, with attached fragments of fibroadipose tissue.


Figure 2 (high power): There are spindled fibroblast-like cells embedded in a loose fibromyxoid matrix, as well as other cells with abundant basophilic cytoplasm, resembling ganglion cells. Occasional binucleate cells are seen. Mitotic figures are rare.



The history of a rapidly-growing superficial nodule in a middle-aged person, usually on an extremity, in combination with the histologic findings described, is characteristic of proliferative fasciitis, which is considered by many to be a variant of nodular fasciitis. These are self-limiting, benign reactive processes whose etiology is unknown. Their development is sometimes preceded by soft tissue trauma. Complete excision is almost always curative, with local recurrence rare.

Nodular fasciitis is generally considered to be more circumscribed than proliferative fasciitis and lacks the plump ganglion-like cells characteristic of the latter. Both may occur in subcutis, muscle, or fascia. The cells of nodular or proliferative fasciitis are immunoreactive for vimentin, smooth muscle actin and muscle-specific actin, but negative for desmin or S-100 protein.

The differential diagnosis is wide. The lesion may be misdiagnosed as fibrosarcoma. The cells in the latter are usually densely packed in classic “herringbone” fashion and demonstrate more nuclear pleomorphism and hyperchromaticity, with numerous mitotic figures. Myxoid malignant fibrous histiocytoma usually occurs in patients over 50 and presents as a larger, deeper mass. The nuclei of MFH cells are strikingly pleiomorphic.


Proliferative fasciitis




  1. Enzinger FM, and Weiss SW (1995). Soft Tissue Tumors. Mosby, St. Louis. pp. 165- 199.



  2. Lundgren L, Kindblom L-G, Willems J, Falkmer U, and Angervall L (1991). Proliferative myositis and fasciitis. A light and electron microscopic, cytologic, DNA- cytometric and immunohistochemical study. APMIS 100:437-448.




James Mandell, M.D., Ph.D.
Department of Pathology
University of Virginia Health System



Philip H. Cooper, M.D.
Department of Pathology
University of Virginia Health System



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