F 58, pruritic cystic lump behind right ear.



    A 58-year-old Caucasian female presented to the clinic with a pruritic cystic lump behind her right ear. The nodule had been present for an unknown period of time and she attributed it to an insect bite. An infection was suspected and she was treated with antibiotics. One month later she presented to the hospital again with complaints of enlargement of the lump and pain. Physical examination showed a soft and spongy lesion with purple streaks behind the right ear. A sebaceous cyst with infection was suspected. An incision was performed with drainage of some yellow-pink fluid that was negative for microorganisms on culture. At the follow-up visit 1 month, later the purple-blue mass in the right postauricular area appeared to be much larger, measuring 8x5x3 cm (Fig. 1). The lesion extended from the superior to the inferior edge of the postauricular groove without involvement of the pinna. There were areas of superficial breakdown and drainage of some serosanguineous and purulent fluid. Multiple enlarged, firm, and mobile lymph nodes were palpated in the right mandibular region and in the right anterior and posterior triangle of the neck.

    An incisional biopsy of the lesion showed a dermal neoplasm composed of infiltrating irregular, vascular or sinusoidal anastomosing channels (Fig. 2A). Slit-like vessels with dissection of the dermal collagen were prominent. The vessels were lined by a disorganized proliferation of polyhedral atypical endothelial cells with a high nucleus to cytoplasm ratio, scant amphophilic cytoplasm, and dark blue nuclei. Micropapillae of the neoplastic cells with a hobnail appearance were seen projecting into the lumen of the neoplastic vessels (Figs. 2A and 2B). There were also focal clusters of solid tumor cells. By immunohistochemical staining, the neoplastic cells showed strong positivity to CD31, CD34 (Fig. 3A) and Factor VIII (Fig. 3B) with a moderate to high proliferative rate by Ki67 staining (Fig. 3C). A high grade angiosarcoma of the scalp was diagnosed. A subsequent biopsy of a cervical lymph node revealed many atypical cells that were highly suspicious for metastatic malignancy. The patient expired 2 months after her diagnosis was made and 5 months after the presentation to the clinic.