Papillary craniopharyngioma mistaken for recurrent Rathke's cleft cyst: a case report of a seven-year diagnostic pitfall involving BRAF V600E testing

Introduction Rathke's cleft cysts (RCC) and craniopharyngiomas are clinically, radiologically and histopathologically similar lesions that are difficult to distinguish and require different surgical treatments. Many authors support the hypothesis that these represent two spectra of the same pathology. Case report We present the case of a 53-year-old man who, because of general malaise, was examined by an endocrinologist and found to have partial hypopituitarism and indirect hyperprolactinemia. Consequently, he underwent a head MRI, which revealed an intra-suprasellar cystic lesion. Surgical fenestration of the cyst was performed, and tissue samples were collected for histopathological examination, which confirmed a diagnosis of RCC. Over the years, follow-up imaging revealed a recurrent, enlarging cyst; therefore, the patient underwent reoperation 7.5 years later. This time, histology revealed a papillary craniopharyngioma (PC). Re-examination of the specimen from the first surgery also confirmed presence of PC on the same specimen section as RCC, with the initial false-negative result attributed to suboptimal staining. Conclusion Apparent progression from RCC to craniopharyngioma should prompt re-examination of the original pathology before it is interpreted as true transformation. In our patient, conservative fenestration was followed by recovery of corticotroph function that lasted seven years, whereas subsequent radical surgery resulted in new corticotroph and thyrotroph deficiency without complete resection, highlighting the need for caution with early aggressive surgery in cystic sellar lesions of uncertain histology.