RESUMO
BACKGROUND: Lynch syndrome (LS) is a cancer-predisposing condition resulting from germline mutations in deoxyribonucleic acid mismatch repair genes. Patients are at high risk for a multitude of tumors, but no reports of undifferentiated sellar carcinomas have previously been described. CASE DESCRIPTION: A 56-year-old female with LS due to MSH2 and MSH6 mutations presented with panhypopituitarism and a sellar mass. She was initially diagnosed with pituitary apoplexy and treated nonoperatively. The mass self-resolved. The mass recurred 2 years later, and she underwent endoscopic endonasal biopsy demonstrating an undifferentiated carcinoma of the sella with MSH2 and MSH6 loss. The tumor was negative for pituitary markers and weakly positive for p63. The patient further developed lung and bone metastases and was treated with radiation and chemotherapy. CONCLUSIONS: This is the first report of an undifferentiated carcinoma of the sella. Our patient harbored a diagnosis of LS and demonstrated local tumor recurrence and aggressive systemic progression. Patients with LS should undergo close follow-up and active surveillance to detect and treat these aggressive lesions in a timely manner.
