Background. Microcystic variant of urothelial carcinoma is one of the new variants of urothelial carcinoma that was added to the WHO classification in 2004. Aims. To review the literature on microcystic variant of urothelial carcinoma. Methods. Various internet search engines were used to identify reported cases of the tumour. Results. Microscopic features of the tumour include: (i) Conspicuous intracellular and intercellular lumina/microcysts encompassed by malignant urothelial or squamous cells. (ii) The lumina are usually empty; may contain granular eosinophilic debris, mucin, or necrotic cells. (iii) The cysts may be variable in size; round, or oval, up to 2？mm; lined by urothelium which are either flattened cells or low columnar cells however, they do not contain colonic epithelium or goblet cells; are infiltrative; invade the muscularis propria; mimic cystitis cystica and cystitis glandularis; occasionally exhibit neuroendocrine differentiation. (iv) Elongated and irregular branching spaces are usually seen. About 17 cases of the tumour have been reported with only 2 patients who have survived. The tumour tends to be of high-grade and high-stage. There is no consensus opinion on the best option of treatment of the tumour. Conclusions. It would prove difficult at the moment to be dogmatic regarding its prognosis but it is a highly aggressive tumour. New cases of the tumour should be reported in order to document its biological behaviour. 1. Introduction Since microcystic variant of urothelial carcinoma was added to the WHO classification, very few cases have been reported in the literature, and in view of this most practitioners would be unfamiliar with the biological behaviour of this rare type of tumour. The ensuing paper contains literature review of microcystic variant of urothelial carcinoma. 2. Methods Various internet search engines including Google, Google Scholar, PubMed, Educus. and UpToDate were used to identify the literature including case reports, case series, and review papers on microcystic variant of urothelial carcinoma for the review of the literature on microcystic variant of urothelial carcinoma. The key words that were used included microcystic variant of urothelial carcinoma and microcystic transitional cell carcinoma. In all 17 documentations were found which were relevant to the aetiology, presentation, diagnosis, management, and outcome of microcystic variant of urothelial carcinoma. 3. Literature Review 3.1. Overview 3.1.1. Definition and Terminology Microcystic variant of urothelial carcinoma is one of the variants of
A. Paz, L. Rath-Wolfson, D. Lask et al., “The clinical and histological features of transitional cell carcinoma of the bladder with microcysts: analysis of 12 cases,” British Journal of Urology, vol. 79, no. 5, pp. 722–725, 1997.
D. Pacchioni, M. Bosco, E. Allia, B. Mussa, G. Mikuz, and G. Bussolati, “Microcystic urothelial cell carcinoma with neuroendocrine differentiation arising in renal pelvis. Report of a case,” Virchows Archiv, vol. 454, no. 2, pp. 223–227, 2009.
V. Barresi, A. Ieni, C. Magno, and G. Barresi, “High-grade urothelial carcinoma of the urinary bladder showing acquisition of microcystic histology in the penile metastasis: histogenetic considerations,” Pathology Research and Practice, vol. 205, no. 8, pp. 568–571, 2009.
I. Alvarado-Cabrero, D. Pérez-Montiel, and O. Hes, “Multicystic urothelial carcinoma of the bladder with gland-like lumina and with signet-ring cells. A case report,” Diagnostic Pathology, vol. 3, no. 1, article 36, 2008.
X. Leroy, E. Leteurtre, A. de la Taille, D. Augusto, J. Biserte, and B. Gosselin, “Microcystic transitional cell carcinoma: a report of 2 cases arising in the renal pelvis,” Archives of Pathology and Laboratory Medicine, vol. 126, no. 7, pp. 859–861, 2002.
A. Sari, M. A. Uyaroglu, M. Ermete, M. Oder, C. Girgin, and C. Dincer, “Microcystic urothelial carcinoma of the urinary bladder metastatic to the penis,” Pathology and Oncology Research, vol. 13, no. 2, pp. 170–173, 2007.
D. Radopoulos, K. Kalyvas, R. Kotakidou, K. Panagiotopoulou, V. Katsikas, and M. Papathanasiou, “Case report: microcystic transitional cell carcinoma of the urinary bladder,” International Urology and Nephrology, vol. 37, no. 2, pp. 291–293, 2005.
G. Pomara, I. Pastina, M. Simone, P. Casale, G. Marchetti, and F. Francesca, “Penile metastasis from primary transitional cell carcinoma of the renal pelvis: first manifestation of systemic spread,” BMC Cancer, vol. 4, article 90, 2004.