“Unusual Presentation of Epitheloid Dermatofibroma- Rare Case Report”

Abstract

Dermatofibroma is a commonly occurring cutaneous entity usually centered within the skin’s dermis. Dermatofibromas are referred to as benign fibrous histiocytomas of the skin, superficial/cutaneous benign fibrous histiocytomas, or common fibrous histiocytoma. These mesenchymal cell lesions of the dermis clinically are firm subcutaneous nodules that occur on the extremities in the vast majority of cases and may or may not be associated with overlying skin changes. A 20 years old male presented to ENT OPD, at a private hospital, with complaints of a huge mass over right side of face since 15 years, which was slowly growing and not associated with pain. On clinical examination, hard, non tender, lobulated cauliflower like mass located over right side of face extending from right side temporal region to upper border of mandible from superior to inferior. From anterior to posterior it was extending from lateral 1/3rd of forehead and covering lateral canthus of right eye upto right side tragus. We have taken incisional biopsy which was suggestive of dermatofibroma. Then surgery was performed with patient’s consent. Excision with 1 cm free margin was done. Raw area was covered with full thickness skin grafting and advancement flap. We found no recurrence till date. Dermatofibroma in the head and neck region is less common and often present a difficult differential diagnosis like Dermatofibrosarcoma protuberans, Kaposi Sarcoma, Basal cell carcinomas. The aim of case report is to represent case of dermatofibroma of epitheloid variety which is unusual in size.

Introduction

Dermatofibroma is a common benign fibrohistiocytic neoplasm which uncommonly involves the face and neck. It typically presents as a firm to hard, often hyperpigmented, slow-growing, plaque or nodule [1]. Dermatofibroma, is one of the most common cutaneous soft-tissue lesions, accounting for approximately 3% of skin lesion specimens received by dermatopathology laboratories. In addition to common fibrous histiocytoma, other variants described to date include aneurysmal, hemosiderotic, cellular, epithelioid, atypical, lipidized, clear cell, palisading, atrophic, keloidal, granular cell, myxoid, lichenoid, balloon cell and signet-ring cell variants. A significant proportion of dermatofibromas are associated with previous minor local trauma, especially insect bites. We have reported an unusual case of dermatofibroma over face in a young male patient [2].

Case History

A 20 year old male presented to ENT OPD with complain of huge mass over right side of face since 15 years. That is slowly growing and not associated with pain.

On clinical examination, hard, non tender, lobulated cauliflower like mass located over right side of face extending from right side temporal region to upper border of mandible from superior to inferior. From anterior to posterior it was extending from lateral 1/3^rd of forehead and covering lateral canthus of right eye upto right side tragus. (Fig. 1).

Fig. 1.

Swelling over right side of face

Incisional biopsy was taken from mass. Histopathological report was suggestive of dermatofibroma.

Patient was planned for surgery after taking proper consent for excision and skin grafting. Tumor was excised from its base with 1 cm free margin in periphery. (Fig. 2). Main specimen was sent for histopathological examination. Report was suggestive of epitheloid variety of dermatofibroma.

Fig. 2.

Raw area after excision

raw area was approx. 15*10 cm(Fig. 3).

Fig. 3.

Main specimen

Raw area below lateral canthus and tragal cartilage was covered with skin flap advancement from upper part of neck region. Area above that was covered with full thickness skin grafting from thigh. (Fig. 4) Patient was treated post-operatively with 14 days antibiotic and operative site dressing regularly. After 14 days, dermis layer was found very well taken up with rejection of epidermis at some place. After removal of necrotic epidermis region, it was left behind for secondary healing with regular dressing with placental extract gel. At the end of 3 months, patient came to opd with healthy operative site. (Fig. 5).

Fig. 4.

Raw area closure with skin grafting and advancement flap

Fig. 5.

Pre op and post op (3 months) comparision

We found no recurrence till date in this case.

Discussion

Dermatofibroma is a benign skin lesion, characterized by a reactive fibroblastic proliferation of the skin, usually secondary to minor trauma or insect bites. Clinically, it consists of a firm asymptomatic nodule or papule, 3 to 20 mm in size, with variable colors [3].

The most common location for the dermatofibromas was the limbs (74%), followed by the trunk (23%) and neck and face (3%) [2]. While Seper et al. found that of all the cellular and atypical types, about 20% are localised in the head and neck region, they usually grow faster and are greater in size than the other subtypes, and tend to recur locally (up to 26%) [4].

There are many variant of dermatofibroma described till date. We found epitheloid variety of dermatofibroma in our case which is unusual in size and location.

Alves JVP et al. has described variant of dermatofibroma in detail [2]. Epithelioidhistiocytoma was originally described by Jones et al. [5] Unlike most histiocytomas, it has a slight male predominance. Clinically, it presents as a polypoid red nodule. On histopathological examination they found at least 50% of the lesion is composed of rounded or polygonal epithelioid cells with abundant eosinophilic cytoplasm and round nuclei containing small eosinophilic nucleoli [2].

In our study in histopathology examination, dermis shows cells arranged in short sheets and curlicue pattern. Most of cells are spindled histiocytic with epitheloid morphology with eosinophilic cytoplasm and round vescicular nuclei with prominent nucleoli. No basal activity present. The classical histopathological features consist of ill-defined intersecting bundles of spindle cells with collagen trapping.

Camara M F et al. found dermatofibroma exhibits the Fitzpatrick’s dimple sign when laterally compressed. This skin tumor usually persists indefinitely, affecting mainly young adults with a slight predilection for females. It may appear as single or multiple lesions and is usually found on the lower limbs [3]. Benign fibrous histiocytomas (BFH) are frequently found in sun-exposed skin of the extremities and of the head and neck. They are among the most common soft tissue lesions of the skin. Reported incidence of malignant transformation is around 1% [4].

It is more important to differentiate benign dermatofibromas from more advanced and aggressive neoplasms that may appear similar to dermatofibromas in some cases. Myers DJ et al.described various differential diagnosis of dermatofibroma [6].

Dermatofibrosarcoma protuberans (DFSP) is a low to intermediate grade, locally aggressive neoplasm that can be mistaken for a benign dermatofibroma. Thankfully, there are several distinguishing features. DFSP is characteristically more cellular and will involve more of the subcutis, displaying “honeycomb” entrapment of subcutaneous fat. In difficult cases, immunohistochemical staining can be very helpful DFSPs are also often much larger lesions, with average diameters of 5 cm, according to one study [6].

Kaposi Sarcoma, also composed of a spindled cell proliferation within the dermis, may be mistaken for the aneurysmal variant of dermatofibroma as Kaposi Sarcoma characteristically displays red blood cells between spindled cellular areas and vascularity. However, Kaposi Sarcoma should display HHV-8 positivity and may also stain positive for CD31, CD34, and D2-40 [6].

Basal cell carcinomas (BCC) can mimic a dermatofibroma with overlying follicular induction, which refers to epidermal hyperplasia such as basaloid proliferation. This differentiation is usually most difficult in superficial biopsies, which may miss the underlying dermatofibroma. There may even be peripheral palisading in these lesions, a characteristic finding usually of BCCs. Important differentiating factors include the presence of CK20 positive [6].

In our case, we have done wide local excision with 1 cm free margin. In post operative period, chemotherapy or radiotherapy was not given. Patient was observed for 1 year regular follow up. No recurrence was found till date in our case. Hongxu Chen et al. suggested that the best way to treat BFH in skull is surgical radical resection. The efficacy of adjuvant radio-chemotherapy after surgery is unknown [7]. Damera Srikanth et al. have done similar case of BFH with wide local excision only without adjuvant chemotherapy or radiotherapy [8]. Fewer than 5% of cutaneous fibrous histiocytoma recur following local excision and there are no reported cases of recurrence in mouth. Local excision of these lesions show no major functional or cosmetic morbidity [9]. Radiation therapy and chemotherapy have currently no major role in management of benign fibrous histiocytoma [10].

Conclusion

Dermatofibroma in the head and neck region is less common and often present a difficult differential diagnosis. The aim of case report is to represent case of dermatofibroma of epitheloid variety which is unusual in size. The prognosis of dermatofibroma is excellent. The results of this study support local excision as definitive treatment of dermatofibroma of face. When pathologically clear margins are found, the incidence of local recurrence is unlikely. Radiation therapy and chemotherapy have currently no role in the management of dermatofibroma.