A 40-year-old male patient presented with a painful nodule in the lower part of right leg. He related that the nodule had remained stable in size and non-painful for 4 years. Over the past 6 months, it began to enlarge and became painful. There was no history of trauma, and his personal or family history was negative for any malignancy. On palpation, an irregular, firm, erythematous, mobile, tender mass measuring 3.5 × 2.3 × 1.7 cm, was noted just above the lateral malleolus of the right leg. Popliteal and inguinal lymph nodes were not palpable. A thorough clinical examination did not reveal other relevant cutaneous lesions.
Systemic examination and investigations including complete blood count, fasting blood sugar level, liver function test, and renal function test were within normal limits. Hepatitis B virus surface antigen and human immunodeficiency virus enzyme-linked immunosorbent assay were non-reactive.
The patient underwent local excision of the tumor. A curvilinear approach was employed for maximum exposure of the tumor, which was removed completely and submitted for histopathological examination.
Gross inspection revealed a lobulated, tan-grey, firm mass, measuring 3.5 × 2.3 × 1.7 cm, and partly covered with skin. Light microscopy revealed a poorly-delineated dermal neoplasm, extending into the underlying superficial parts of the subcutis. The tumor was composed of nests and fascicles of spindle-shaped to epithelioid cells, with pale eosinophilic cytoplasm and vesicular nuclei with prominent nucleoli infiltrating a collagenous stroma. Mitoses, including atypical, amounting to 7-8 mitotic figures per 10 high power-fields were noted. Intracytoplasmic melanin pigment was not noted. The epidermis did not show any significant increase in melanocytes within the basal layer, junctional activity or pagetoid spread of tumor cells [Figures and ].
Clear cell sarcoma: low power revealed a dermal malignancy composed of tumor cell nests and fascicles delineated by fibrous septa. No junctional activity or pagetoid spread of abnormal melanocytes (H and E, ×100)
Clear cell sarcoma: Higher magnification showing spindled to epithelioid cells with pale eosinophilic cytoplasm and vesicular nuclei with prominent nucleoli (H and E, ×400)
On immunohistochemistry, the tumor cells exhibited strong positivity for vimentin and focal positivity for Melan A and HMB-45. The neoplastic cells stained negative for S-100 protein, pancytokeratin, epithelial membrane antigen, and CD 31 . A diagnostic dilemma occurred between MM and cutaneous CCS. However, in view of lack of epidermal changes and absence of any identifiable primary cutaneous neoplasm, a final diagnosis of cutaneous CCS was rendered.
Figure 3 Immunohistochemical staining showing (a), Intense cytoplasmic immunopositivity for vimentin (Vimentin ×400); (b), Cytoplasmic immunoreactivity for Melan-A (Melan-A × 400); (c): Focal cytoplasmic immunoreactivity for HMB-45 (HMB-45 ×400); (more ...)
The patient declined to undergo revision of the initial surgery with a wider margin of resection and sentinel lymph node biopsy and discharged himself against medical advice.