[Neuroendocrine tumor associated with an intestinal cyst: a case report]. / Tumor neuroendocrino asociado con quiste intestinal: presentación de un caso.

Intestinal (tailgut) cysts or retrorectal cystic hamartomas are rare benign lesions that are included in the category of developmental cystic lesions. Their origin is still uncertain, although several hypotheses have been proposed to explain their development. They are located mainly in the presacral (retrorectal) space and predominately affect middle-aged women (40-60 years). Taking into account location and histological characteristics, the main differential diagnoses include epidermoid cysts, duplication cysts and teratomas. Malignant transformation of these lesions is rare and preferentially into adenocarcinoma and neuroendocrine tumors. We present a case of an intestinal cyst associated with a well-differentiated neuroendocrine tumor (G1) in a 63-year-old woman.

[Cystic tubulopapillary adenoma with apocrine differentiation and BRAF V600E mutation. A case report and review of the literature]. / Adenoma tubulopapilar quístico con diferenciación apocrina: descripción de un caso con mutación de BRAF V600E y revisión de la literatura.

Syringocystadenoma papilliferum (SCAP), tubular adenoma (TA) and hydrocystoma (HC) are benign adnexal tumors. Recently it has been suggested that these lesions belong to the same morphological spectrum: Tubulopapillary cystic adenoma with apocrine differentiation (TPCAa). BRAF and K-Ras (KRAS) mutations have been described in SCAP and TA, but not in HC. Moreover, verrucous epithelial proliferations have been observed in TPCAa. We present a case of TPCAa with BRAF V600E mutation and BRAF VE1 immunohistochemical expression in the SCAP, AT, HC and verrucous hyperplasia components.