Various case reports are present in the literature describing this rare variant of gall bladder carcinoma.1 4
In the case report by Karabulut et al
the patient (a 76-year-old man) died within 3 months in spite of radical surgery and chemotherapy. In our patient, there were a few areas that microscopically showed a conventional adenocarcinoma pattern. However, over 90% of the tumour was composed of sheets of signet ring cells. Additionally, grossly the gall bladder did not show a discrete mass, rather it showed a diffuse thickening of the wall resembling a linitis plastica appearance as seen in signet ring cell type gastric adenocarcinoma. This corresponds to what has been reported in the literature previously.3
Krunic et al5
reported a case of signet ring cell adenocarcinoma of gall bladder with multiple metastases to the skin in the form of nodules on the skin, scalp and perianal area. Multiple metastases to bone were also seen. These developed 1 year after resection, while no visceral metastases were detected after 20 months of follow-up. Naylor et al6
reported a case of signet ring carcinoma presenting with meningeal carcinomatosis. It was only after extensive investigation that a gall bladder primary tumour was detected. Olinici and Vasiu7
reported a composite endocrine cell, typical and signet ring adenocarcinoma of the gall bladder. They suggested the presence of a common primitive cell with the capacity to differentiate to different types of metaplastic epithelium, which supports the hypothesis of a metaplasia–dysplasia–carcinoma sequence. Nishida et al8
reported a human gall bladder signet ring cell adenocarcinoma cell line. It must be mentioned that benign signet ring cell change, in the form of signet ring cell aggregates, sometimes occurs in the gall bladder and colonic mucosa. These may lead to multilayering of the mucosa, but are always confined to the mucosa. There are never any dysplastic changes in the epithelium nor is there any invasion of the submucosa or the muscle wall. However this change is a rare and misleading diagnostic pitfall that must be kept in mind when making a diagnosis of signet ring carcinoma in gall bladder, and indeed more importantly in the colon.9 10
Additional histological investigations such as immunostaining with CK7, CK20 and CDX2 may be helpful in this regard. It is important to rule out entities such as carcinosarcoma and lyphangiosarcoma of the gall bladder wall. There are case reports in which these rare tumours are described.
- Primary signet ring carcinoma is a rare histological variant of gall bladder carcinoma.
- Before diagnosis, secondary involvement of gall bladder from carcinoma of stomach or colon should be ruled out by additional histological investigation such as additional immunohistochemical staining with cytokeratin (CK)7, CK20 and Caudal type homeobox (CDX)2.
- Primary signet ring carcinoma shows surface dysplastic epithelium. Since very few cases have been reported, information regarding behaviour and prognosis is limited. It should also be mentioned that although there is still controversy about the role of surgery in patients with advanced gall bladder cancer, such patients could still benefit from an aggressive, radical and potentially complete curative resection.