Dermatofibroma Botryoides on Nipple: A Report.

Sir,

A dermatofibroma is a round, brown to red-purple growth commonly found on the lower extremities. It is also referred to as benign fibrous histiocytoma of the skin. Its etiology is unknown, but often occurs after local trauma.[1] The diagnosis of a dermatofibroma is clinical but requires an excisional biopsy with removal of subcutaneous fat in cases of diagnostic uncertainty.[2] No treatment is necessary unless it is symptomatic (e.g. tenderness), in which case a complete excision is recommended.[2] Alternatively, we suggest that corticosteroids may be directly injected into the lesion for non-excisional management.

Histologically, there is a dermal and often superficial subcutaneous proliferation of oval to spindle cells, appearing as histiocytes and spindle-shaped cells, respectively. These cells resemble fibroblasts and myofibroblasts. Histopathologic examination may reveal hyperplasia of the overlying epidermis and increased melanin in the basal layer (“dirty fingernail” sign). Several histologic variants of dermatofibromas have been described including cellular, aneurysmal, atypical (dermatofibroma with monster cells), epithelioid, atrophic, polypoid, dermatofibroma with spreading satellitosis, and deep (subcutaneous).[2345] We present a unique architectural variant.

The patient was a 51-year-old woman who presented with a 4.5-centimeter, grape-like hard lesion with 20 spheroid grape-like structures on her right nipple with progressive enlargement over the last four years. The patient had previously worked as an exotic dancer, where she routinely hung and twirled eight-inch tassels from her nipples in a cyclical manner. She had been inactive in her profession for two years prior to presentation. The lesion was pruritic, but otherwise asymptomatic. Histologically, there were acellular masses of collagen, with sparse fibroblasts and absence of atypia [Figure 1]. The lesion was strikingly positive for Masson trichrome stain, signifying the presence of collagen [Figure 2]. The lesion was negative for “cigar-shaped” nuclei and other markers of smooth muscle. It was also positive for factor XIIIa [Figure 3], whereas factor 34a stained only blood vessels. Results from immunohistochemical testing with antibodies to factor XIIIa are frequently positive in dermatofibroma.[2]

Figure 1

Histopathology showing acellular masses of collagen with sparse fibroblasts (H and E, x155)

Figure 2

Masson trichome stain showing nodularity and high collagen content (×155)

Figure 3

Fibrotic nodule with factor XIIIa staining dermal fibroblasts brown (×155)

To our knowledge, this is the first dermatofibroma showing a botryoid architecture, especially in this anatomic region. The word botryoid is derived from the Greek word, meaning a bunch of grapes. The histological findings of dermatofibroma botryoides are otherwise typical of hypocellular dermatofibromas except the lesions appear histologically and clinically as globular masses.

It is important to recognize that a dermatofibroma may present with this architecture in order to be able to distinguish it from other benign and malignant lesions. Based on the clinical or histological findings, the differential of a dermatofibroma may include a leiomyoma, pilomatricoma, atypical fibroxanthoma, juvenile xanthogranuloma, dermatofibromsarcoma protruberans, primary cutaneous carcinoma, or metastatic carcinoma of the skin.[2] Breast malignancy was also a concern in this case given the location.

In cases with similar preliminary clinical and histologic finding as this patient, dermatofibroma with botryoid architecture should be on the differential; and, it may be prudent to obtain Masson trichrome, factor XIIIa and 34a stains to further evaluate for a dermatofibroma.

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Conflicts of interest

There are no conflicts of interest.