Abstract
We present a case of a 61y.o male who presented with anew left pre-auricular PDS with osteoclast-like giant cells and invasive squamous cell carcinoma (SCC) of the right preauricular skin. The preauricular lesions were discovered one year after patient undergone MOHS surgery for SCC of the scalp. PET/CT confirmed the presence of two hypermetabolic nodules. Histology showed a dermal tumor with extensive osteoclast-like giant cells, nuclear atypia and mitotic activity invading into the subcutis. Immunostains P40, SMA, CD45, SOX10, ERG, desmin, CK5/6, CK34BE12, and p63 were negative. This staining pattern supported the diagnosis of PDS with osteoclast-like giant cells. The patient completed two rounds of carboplatin/Taxol chemotherapy with great response.
Although its metastatic risk has been estimated to be at less than 5%, its real outcome is uncertain due to its rare nature and lack of homogenous criteria used to report cases. Because PDS has an increased risk of metastasis and local recurrence, our case emphasizes the importance of recognizing this rare neoplasm and distinguishing it from atypical fibroxanthoma, sarcomatoid SCC melanoma and other sarcomas. This case helps clinicians be more aware of unusual variants of this rare tumor and appropriate management