Kenjiro Misu

Gastrointestinal Obstruction due to Solitary Lymph Node Recurrence of Alpha-Fetoprotein-Producing Gastric Carcinoma with Enteroblastic Differentiation

We report an unusual case of alpha-fetoprotein (AFP)-producing gastric carcinoma with enteroblastic differentiation. A 75-year-old woman was admitted to our hospital with occasional upper abdominal discomfort. We performed gastroscopy and observed a type 2 tumor, primarily in the pyloric region. Histological examination of biopsies confirmed gastric adenocarcinoma. Based on these findings, we diagnosed gastric adenocarcinoma and performed laparoscopic distal gastrectomy with lymph node dissection. Histological examination revealed an invasive lesion composed of adenocarcinoma with a tubulopapillary growth pattern. Tumor cells were cuboidal in shape with characteristically clear cytoplasm rich in glycogen. Two regional lymph node metastases were seen microscopically. Immunohistochemically these cells were positive for AFP, carcinoembryonic antigen, caudal-type homeobox transcription factor 2 and common acute lymphoblastic leukemia antigen. The final diagnosis was AFP-producing gastric carcinoma with enteroblastic differentiation. 26 months after initial surgery, the patient was readmitted to our hospital for gastrointestinal obstruction due to lymph node recurrence.

PEDUNCULATED GASTRIC SIGNET RING CELL CARCINOMA

Signet ring cell carcinoma (SRCC) is characterized by poor ductal formation and a diffuse progression pattern and generally presents as a depressed lesion in the majority of cases. We describe here an extremely rare case of gastric SRCC that presented as a pedunculated lesion. We hypothesize that the major factor responsible for the elevation of this lesion was proliferation of signet ring cells that did not lose their mutual connections. Among the two cases of early elevated‐type gastric SRCC that have been reported in the literature, this is the first case of pedunculated intramucosal SRCC. Pathological examination revealed no cancer cells in the basal part of the elevated lesion. The cellular morphology was consistent with SRCC, although the ductal structure was well preserved and more similar to well‐differentiated adenocarcinoma. Endoscopic examination showed a smooth‐surfaced lesion with no depressed region around the basal part of the elevated lesion. Because these findings differ significantly from previous reports of elevated SRCC, this report provides further insight into the nature of SRCC.