Abstract:

An 87-year-old male with a history of multiple prior basal cell carcinomas presented for evaluation and treatment of a non-painful rapidly growing ulcer on the anterior left leg. Physical examination showed a 3.5 x 2.0 cm friable red-pink plaque clinically suspicious for basal cell carcinoma. Shave biopsy of the lesion was performed, and microscopic examination of the biopsy showed an ulcerated basal cell carcinoma with protuberant granulation tissue in the area of ulceration. Adjacent to the ulceration/granulation tissue, a basal cell carcinoma with topographically varied histology was noted. Superficial, nodular and infiltrative basal cell carcinoma nests were identified at the periphery of the tissue fragment. Some of the nests demonstrated follicular or infundibulocytic differentiation consisting of keratin-filled cysts. In the center of the lesion, a large nodule was formed by marked extracellular eosinophilic material associated with multiple small basal cell carcinoma nests. The extracellular material stained blue with Trichrome and pink with PAS. A Congo Red stain did not show Congophilia or birefringence. Immunohistochemically, the tumor nests stained strongly and diffusely with Cytokeratin AE1/AE3 and BerEp4. EMA and CEA were negative in tumor nests. CD34 highlighted dermal and tumor associated vessels. BCL-2 stained foci of the basal cell carcinoma tumor nests. CK20 was negative within tumor nests. We present the first reported case, to our knowledge, of a basal cell carcinoma with marked redundant basement membrane material forming a dermal nodule and simulating tumor-associated amyloid.

Financial Disclosure:
No current or relevant financial relationships exist.

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Anthony Wheeler, MD