Genomic profile of a primary squamous cell carcinoma arising from malignant transformation of a pineal epidermoid cyst.

Malignant transformation of intracranial epidermoid cysts is a rare occurrence. We present the second case of such an event occurring in the pineal region and the first case sent for detailed genomic profiling. MRI demonstrated two lesions: a cyst in a quadrigeminal cistern with restricted diffusion on DWI-weighted images and an adjacent, peripherally enhancing tumor with cerebellar infiltration. Both the lesions were completely resected with a small residual of the epidermoid cyst. The final pathology of both lesions was consistent with epidermoid cyst and squamous cell carcinoma (SCC), respectively. The tumor specimen was sent for comprehensive genomic profiling which revealed stable microsatellite status and loss of CDKN2A/B, MTAP (exons 2-8), and PTEN (exons 6-9). Although reports of primary SCC originating from the epidermoid cyst have been previously described, this is the first description of the genomic profile of such a tumor.

A rare case of primary rectal squamous cell carcinoma diagnosed by endoscopic ultrasound.

Primary squamous cell carcinoma (SCC) of the rectum is a very rare entity making up to 0.1-0.25/1,000 cases of all colorectal cancers. Here, we present the case of an otherwise healthy 63-year-old female who presented with progressive pelvic discomfort, new onset constipation and a complex mass in presacral region on imaging which was proved to be poorly differentiated SCC of the rectum. The correct diagnosis was achieved by fine needle aspiration (FNA) via endoscopic ultrasound (EUS-guided FNA) as initial conventional colonoscopy failed to establish the diagnosis. Patient completed neoadjuvant chemo-radiation and her tumor was successfully resected. She is following up with oncology clinic for monitoring and further management.