The curious case of a forehead metatypical basal cell carcinoma.

The risk of developing basal cell carcinoma (BCC) during lifetime varies between 29-55%, while for squamous cell carcinoma (SCC) varies between 7-11%. Between them, considered to be a BCC, there is a particular histological type, named metatypical basal cell carcinoma (MTC) or basosquamous cell carcinoma (BSCC). In this paper, we presented a rare case of metatypical carcinoma of the forehead with an interesting history of unexpected recurrences, underlining the clinical, therapeutic and histological essential aspects that may come in use to other clinicians in managing this type of cancer. In this case, the last recurrent tumor invaded the external layer of the frontal bone and needed a temporo-parietal flap to cover the large defect, which was previously covered in 2014 using skin grafts. Using Hematoxylin-Eosin (HE) staining, the histological assessment revealed a basosquamous carcinoma (IDO-O 8094/3, according to World Health Organization). In addition to the histological aspects revealed using HE staining, in this case, diffused tumor cells were p63 nuclear positive, which according to Bircan et al. (2006), it is strongly and diffuse reactive in 82.1% differentiated, in 77.8% of superficial and in 72.3% of solid undifferentiated BCCs. The aggressive behavior was revealed by tumor's dimension, local invasion of the frontal bone with high mitotic rate as seen in the van Gieson and HE staining, also by the number of recurrences. The prognosis of this case is reserved due to the number of recurrent tumors, immunohistochemistry anomalies, involvement of the external layer of the frontal bone, tumor site, gender, poor remaining reconstructive procedures in case of a relapse, thus, close follow-up is to be recommended for a period of minimum five years. Recurrent tumors raise treatment difficulties regarding the reconstruction procedure of the defect after wide surgical excision. Therefore, the aggressive behavior of the MTC should be taken into consideration in clinical practice.