Metastatic signet ring cell adenocarcinoma of the bladder: responsive to treatment?

Abstract

Signet ring cell variant of mucinous adenocarcinoma of the urinary bladder is an exceptionally rare urologic malignancy, generally felt to be resistant to chemotherapy and radiotherapy. We describe a case of this malignancy with unusual sites of metastasis and an unexpectedly good response to treatment.

Fig. 1.

This is an image of a well-circumscribed mass, 6.5 cm in diameter and 2.5 cm in thickness, occupying the dome of the bladder. There was an exophytic growth pattern, and the outer surface was covered in a thick gelatinous material.

Fig. 2.

(A) Hematoxylin & Eosin stain: Roughly half of the tumour volume was occupied by mucin pools or lakes, and one third of the tumour cells had signet ring cell morphology. (B) metastasis to lower lip had similar morphology and immunohistochemical profile. (C) CDX-2 positivity of signet ring cells. (D) Presence of core filamentous rootlets and mucus vacuoles in signet ring cell shown by electron microscopy. Original magnification: × 400 on A, B and C, and × 30000 on D.

Fig. 3.

Radiologic evidence of recurrence. Pre-treatment, Panel A demonstrates a low attenuation mass in the body of the pancreas (arrow), Panel B shows low attenuation lesions anterior to the kidney (thick arrow), and in paraduodenal location (thin arrow), and Panel C shows lesions on either side of the bladder. Panels D, E, and F are equivalent cuts after 7 months of chemotherapy with oxaliplatin and capecitabine.

Fig. 4.

Histologically-proven metastasis to lower lip prior to (Panels A and B), and after chemoradiotherapy (Panels C and D). Note that the centrally necrotic area (Panel B), which had actually fistulized into the oral cavity. This completely healed after treatment.