Atrophic Variant of Dermatofibrosarcoma Protuberans Masquerading as an Alopecic Patch on the Beard

Dear Editor, A young 29-year-old male came to our outpatient department with chief complaints of loss of hair over his beard area for 12 years. The patient had visited multiple physicians before but had no improvement in hair growth. The patch was asymptomatic but gradually progressed in size along with the development of newer patches of alopecia around the larger one. On cutaneous examination, we noticed a skin-colored flat-topped plaque located over the right side of the lower jaw, measuring 5 × 6 cm in dimensions and circular in shape with loss of appendages on the surface of the same. A few satellite alopecic patches, measuring 0.5 cm in diameter, were also seen around the larger plaque [Figure 1(a)]. Based on the history and clinical examination, our differentials were morphea, alopecia mucinosa, and plaque-type dermatofibroma. Dermoscopy of the lesion (Dino-Lite Premier AM4113ZT, 50×) revealed fine arborizing vessels on structureless depigmented areas with a surrounding pigment network. There is a loss of hair follicles on the patch [Figure 1(b)]. Histopathological analysis in low-power view revealed fascicles of densely packed spindle cells located in the deep dermis and extending around fat tissue. Cytologically, the monomorphic spindle cells had elongated, darkly staining nuclei and bland cytoplasm [Figure 2(a) and (b)]. Immunohistochemical (IHC) staining of spindle cells was positive for CD34 while negative for factor XIIIa [Figure 2(c)]. Based on histopathological and IHC findings, our final diagnosis was atrophic dermatofibrosarcoma protuberans (DFSP). The patient was then referred to the plastic surgery department for an excision.Figure 1: (a) Faintly erythematous flat-topped plaque located at the right lower jaw. (b) Dermoscopic image of the lesion showing fine arborizing vessels (black arrows) on structureless depigmented areas (black circles) with surrounding honeycomb pigment network (blue circles) (Dino-Lite Premier AM4113ZT, 50× magnification)Figure 2: (a) Fascicles of densely packed spindle cells located in the deep dermis and extending around fat tissue (H and E stain, 4×). (b) Higher magnification showing monomorphic spindle cells with elongated darkly staining nuclei and bland cytoplasm (H and E stain, 40×). (c) Immunohistochemical (IHC) staining of spindle cells showing positivity for CD34DFSP is an uncommon (0.1%) cutaneous fibroblastic sarcoma of intermediate malignancy showing a characteristic storiform pattern on histology.[1] It mostly involves the trunk and proximal aspects of the extremities and presents as a pink nodule or brownish plaque, surrounded by multiple satellite nodules. It has a high recurrence rate but a low metastatic potential. The subtypes of DFSP are atrophic, fibrosarcomatous, granular, myxoid, pigmented (Bednar tumor), and sclerosing.[2] Atrophic DFSP was first described by Lambert in 1985 as a slow-growing depressed plaque showing decreased dermal thickness by >50% compared with the surrounding dermis histologically. It accounts for only 1.7% (16/937) of all DFSP cases.[3,4] The atrophic variant of DFSP is often misdiagnosed as nevus of Ota, morphea, anetoderma, post-inflammatory hyperpigmentation, hemangioma, and lipoatrophy due to its uncommon morphology.[3] In our case, it presented as an alopecic patch over the beard area, which has not been reported before. Dermoscopy of DFSP reveals a pinkish background, arborizing linear vessels, a pigment network, and, in a few cases, shiny white streaks and structure-less light brown areas.[1] Biopsy remains the gold standard for confirming the diagnosis, along with immunohistochemistry. Table 1 summarizes the differentiating features between classical DFSP and the atrophic variant. Despite being locally aggressive, only 1% of cases show metastases to lymph nodes, lungs, and bones.[6,7] For localized tumors, surgical excision is the gold standard treatment with a preference for Mohs micrographic surgery over wide local excision. Post-surgery radiotherapy is given as an adjuvant. In patients with metastatic disease or inoperable tumors, imatinib is recommended as neo-adjuvant therapy.[7]Table 1: Differences between classical DFSP and atrophic DFSPTo conclude, atrophic DFSP is highly misdiagnosed due to its atypical appearance. Due to its initial benign nature, it is majorly neglected by patients, leading to delayed diagnoses. It is hypothesized that atrophic DFSP represents an early stage before the development of classical DFSP.[2] In this case, the patient had the lesion for 12 years, which was overlooked by him. This case report further adds to the existing literature on DFSP and its variants. Clinicians need to be aware of different variants of DFSP for timely diagnosis and treatment. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.