A Rare Case of Appendiceal Goblet Cell Adenocarcinoma Metastasizing to Ascitic Effusion: Report Highlighting Novel Cytological Features and Clues to Diagnosis

ABSTRACT Goblet cell adenocarcinoma (GCA) is a rare type of appendiceal carcinoma characterized by distinct histological features. It is extremely challenging to diagnose this entity on histopathology and even arduous to identify it on effusion cytology primarily due to its rarity and lack of sufficient literature. We hereby report a unique case of a 45‐year‐old female presenting with abdominal pain, distension, and bilateral ovarian masses. Radiologically, she was suspected of having an ovarian primary. Ascitic fluid smears and cell block sections revealed features of a metastatic adenocarcinoma, exhibiting some distinctive cytomorphological characteristics. The patient subsequently underwent exploratory laparotomy with total abdominal hysterectomy, bilateral salpingo‐oophorectomy, appendicectomy, and omentectomy. Histopathological examination of the appendix and ovarian mass showed a tumor with features of GCA. This case highlights the importance of meticulous cytological evaluation and a systematic approach to rare entities, emphasizing the need for heightened awareness of this condition to avoid misdiagnosis and optimize the treatment strategies.