Perils of diagnosis and detection of subungual squamous cell carcinoma

Abstract

Subungual squamous cell carcinoma often presents with atypical clinical manifestations, which can lead to delays in diagnosis. The presence of a tumor can be masked by the presence of infections or other misleading pathological conditions. The authors report on techniques for adequate biopsy and excision of such tumors. A case of subungual squamous cell carcinoma with invasion into the underlying bone is presented. Clinical histopathological evidence is reviewed along with human papillomavirus typing. Accurate diagnosis requires a high index of suspicion and appropriate tissue sampling.

Keywords: Nail biopsy; Nail deformity; Periungual squamous cell carcinoma; Subungual squamous cell carcinoma.

Fig. 1

Preoperative image showing scant granulomatous tissue along the radial border of the nail fold with nail deformity.

Fig. 2

High power view of a biopsy of the thumbnail fold reveals a tumor composed of whorls of an invasive proliferation of atypical keratinocytes with dyskeratosis and keratin pearls within the dermis. The tumor exhibits distinct intracellular bridges and hyperchromatic, pleomorphic nuclei. Focal areas of single cell keratinization are identified (H&E, original magnification ×400).

Fig. 3

Medium power view of the subsequent distal thumb resection shows deep involvement of the tumor reaching the cortical bone (H&E, original magnification ×100).

Fig. 4

Immunoperoxidase staining for cytokeratin (AE1/AE3) confirms tumor involvement within the bone. Immunohistochemistry AE1/AE3 (original magnification ×400).