Non-metastatic squamous cell carcinoma within a Rathke’s cleft cyst

Abstract

Primary intracranial and sellar squamous cell carcinoma is an extremely rare entity, usually caused by malignant transformation of epidermoid cysts, or very rarely other non-malignant epithelial cysts. Malignant transformation of a Rathke’s cleft cyst has never been described. We present a 49-year-old male patient who presented with a 3-month history of progressive frontotemporal headaches. Imaging revealed a 1.2 cm cystic pituitary mass consistent with a hemorrhagic Rathke’s cleft cyst. The patient underwent trans-sphenoidal resection of the pituitary cyst, and pathologic analysis revealed a squamous cell carcinoma lining a Rathke’s cleft cyst. Extensive imaging and otorhinolaryngologic evaluation revealed no primary source for metastasis. We feel this represents the first case of a patient with a pituitary lesion in which presentation and MRI imaging were consistent with Rathke’s cleft cyst, yet histology revealed squamous cell carcinoma in situ.

Primary intracranial squamous cell carcinoma with a fatal course

“…This last possibility is extremely rare, and only eight cases, other than this, are reported in literature. [ 10 11 12 13 14 15 16 17 ] The clinical characteristics of these cases are summarized in Table 1 . Hamlat et al .…”

“…This last possibility is extremely rare, and only eight cases, other than this, are reported in literature. [10][11][12][13][14][15][16][17] The clinical characteristics of these cases are summarized in Table 1. Hamlat et al classified primary intracranial carcinomas into five categories based on clinicopathological presentation: [8] (1) initial malignant transformation of EC; (2) malignant transformation of remnant EC; (3) malignant transformation with LC; (4) SCC arising from another benign cyst; and (5) other malignancies arising from benign cysts including melanoma, adenocarcinoma, sarcomatoid carcinoma, and osteosarcoma.…”

“…There are no conflicts of interest. [10] 1976 4 Male Parapontine No Died 1 day Nosaka et al [11] 1979 46 Male CPA No Died 7 months Garcia et al [12] 1981 61 Male CPA Radiotherapy Died 9 months Ebisudani et al [13] 1990 68 Male CPA No Died 1 month Jain et al [14] 2003 5 Female Temporal Radiotherapy + chemotherapy Alive 10 months Mallick et al [15] 2012 35 Female Frontal Radiotherapy Alive 24 months O'Neil et al [16] 2016 49 Male Sellar No Alive 12 months Liu et al [17] 2018…”

Homeostatic and tumourigenic activity of SOX2+ pituitary stem cells is controlled by the LATS/YAP/TAZ cascade

“…The resulting non-secreting tumours in our mouse models are composed predominantly of SOX2+ stem cells and display signs of squamous differentiation. Rare cases of squamous cell carcinoma have been reported as primary pituitary tumours (Saeger et al, 2007), but more frequently, arising within cysts that are normally non-neoplastic epithelial malformations (Lewis et al, 1983; O'Neill et al, 2016). In the embryonic YAP-TetO model, where constitutive active YAP (S127A) was expressed during pituitary development, cysts phenocopying Rathke’s cleft cyst, develop by postnatal stages.…”

Homeostatic and tumourigenic activity of SOX2+ pituitary stem cells is controlled by the LATS/YAP/TAZ cascade

“…The resulting non-secreting tumours in our mouse models are composed predominantly of SOX2+ stem cells and display signs of squamous differentiation. Rare cases of squamous cell carcinoma have been reported as primary pituitary tumours 45 , but more frequently, arising within cysts that are normally non-neoplastic epithelial malformations 46, 47 . Although human pituitary carcinomas are only diagnosed as such after metastasis, the tumours generated in our mouse models fit their histopathological profile.…”