Gingival Carcinoma Cuniculatum: A Case Series of Seven Cases with Emphasis on Immunohistochemical and Histochemical Features.

Abstract

Oral carcinoma cuniculatum (CC) is a rare distinct variant of oral squamous cell carcinoma (OSCC) displaying unique clinical and histopathological features. CC is a locally aggressive malignancy with lower metastatic potential and has a tendency to invade the underlying bone yielding nonspecific clinical presentation resembling fungal/bacterial infections or osteomyelitis. Seven rare cases of gingival CC are reported with special emphasis on immunohistochemistry and special stains. Clinical and demographic profile were analysed and all cases were subjected to Ki-67 and p53 immunostaining and Ayoub-Shklar histochemical staining. For comparison, age and gender matched seven cases of conventional OSCC with bony involvement were recruited. IBM SPSS statistics software version 26 (IBM Analytics, Armonk, New York, U.S.) was used to analyse the data. All cases of CC lacked p53 expression in contrast to OSCC and demonstrated intermediate to high proliferation index in stroma also. The keratin staining and cytokeratin profile in OSCC and CC were also found to be statistically different. CC is a rare well differentiated variant of OSCC with different pathways involved in the pathogenesis. Local aggressive and invasive nature could be the result of unique interaction between epithelium and stromal elements. Oral health care provider must be familiar with this uncommon variant of OSCC.