Bladder, ureter & renal pelvis
Urothelial carcinoma-invasive
Microcystic
Topic Completed: 1 December 2015
Minor changes: 15 January 2021
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: Urothelial carcinoma microcystic
Related Topic: Urothelial carcinoma of renal pelvis
Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Sites | Clinical features | Prognostic factors | Case reports | Treatment | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosisCite this page: Andeen NK, Tretiakova M. Microcystic. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/kidneytumormalignanturothelialcarcinomasubtypesmicrocystic.html. Accessed January 24th, 2021.
Definition / general
- Invasive urothelial carcinoma with deceptively bland architecture and cytology, consisting of slit-like or tubular microcysts lined by cuboidal / flattened cells with minimal atypia and intraluminal granular eosinophilic material (Mod Pathol 2009;22:S96)
- Given overall rarity and similarities with microcystic urothelial carcinoma of the bladder, some information and pictures are extracted from bladder, where appropriate
Essential features
- Very rare
- Main biologic significance is deceptively benign features, which may be mistaken for cystitis cystica or glandularis on small biopsies, but is usually deeply invasive
- Histologically may be distinguished by infiltrative growth pattern and variability in cyst size / shape
Terminology
- Also known as urothelial carcinoma with gland-like lumens (Arch Pathol Lab Med 2007;131:1244)
- Recommended to have at least 25% microcystic component to designate as microcystic urothelial carcinoma (Arch Pathol Lab Med 2007;131:1244)
- First described in 1991, in bladder (Am J Clin Pathol 1991;96:635)
Epidemiology
- < 20 cases reported in genitourinary tract including 3 in renal pelvis
Sites
- Bladder, renal pelvis
Clinical features
- Usually deeply invasive
Prognostic factors
- An independent prognostic significance has not been established (Mod Pathol 2009;22:S96)
- Variable prognosis, from highly aggressive (Adv Urol 2013;2013:654751), to similar to conventional invasive urothelial carcinoma (Arch Pathol Lab Med 2007;131:1244)
Case reports
- 55 year old man with microcystic urothelial cell carcinoma (Virchows Arch 2009;454:223)
- 62 year old woman and 73 year old man with microcystic transitional cell carcinoma (Arch Pathol Lab Med 2002;126:859)
Treatment
- No consensus established
Microscopic (histologic) description
- Invasive urothelial carcinoma with slit-like or tubular microcysts, lined by single to multilayered cuboidal or flattened cells with minimal cytologic atypia
- Microcysts are irregular in size / shape, and deeply infiltrative
- Has luminal granular eosinophilic secretions with necrotic cellular debris, sometimes mucinous material or a targetoid appearance (PAS+, Alcian blue+) (Mod Pathol 2009;22:S96, Arch Pathol Lab Med 2007;131:1244)
- May be focally calcified
- May be associated with nested variant of urothelial carcinoma
Microscopic (histologic) images
Contributed by Nicole K. Andeen, M.D. and Maria Tretiakova, M.D., Ph.D.
Deceptively bland urothelial carcinoma composed of infiltrative, microcystic/tubular structures
Deep muscular invasion
CK7 highlights invasive nests
Microcystic and nested features
Images hosted on other servers:
Cysts of various sizes
Neoplastic cystic structures
Cuboidal or flattened cells
Eosinophilic secretions
Low grade UC
Positive stains
- Immunohistochemical properties similar to other urothelial carcinomas: expresses 34βE12, CK7, p63, uroplakin, thrombomodulin
- Intraluminal granular eosinophilic material may be PAS+ and Alcian blue+
Differential diagnosis
- Adenocarcinoma, primary or metastatic: more marked atypia, mitotic activity, necrosis, site specific immunoprofile
- Cystitis glandularis or cystitis cystica: has more lobular growth pattern and regularly sized cystic structures vs. microcystic UC, which has infiltrative growth pattern and marked variability in size and shape of cystic structures. Both are cytologically bland (Mod Pathol 2009;22:S96)
- Nephrogenic adenoma: has circumscribed growth and expresses AMACR and PAX2 vs. microcystic UC, which has invasive growth pattern and will be negative for AMACR and PAX2 (Arch Pathol Lab Med 2007;131:1244, Intensive Care Med 1992;18:S35)
