Journal of Cytology
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Year : 2011  |  Volume : 28  |  Issue : 3  |  Page : 127-130
Fine needle aspiration cytology of a case of micropapillary variant of urothelial carcinoma of bladder

Department of Pathology, Medical College (VIMS), Bellary, Karnataka, India

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Date of Web Publication4-Aug-2011


Neoplastic urothelium has the capacity to demonstrate enormous plasticity. A variety of unusual morphological variants of urothelial carcinoma have been described. Micropapillary variant of urothelial carcinoma is a rare and recently described bladder tumor, associated with poor prognosis. We present the cytological features of micropapillary urothelial carcinoma in a 65-year-old man with bladder mass. The cytological features include tightly cohesive clusters of micropapillary component admixed with urothelial carcinoma. Histopathological sections showed small nests of tumor cells residing within the lacunae. Establishing a diagnosis of micropapillary urothelial carcinoma indicates a high-grade and high-stage tumor with poor outcome, requiring an aggressive therapy. It is thus important for the cytopathologist to recognise micropapillary variant of urothelial carcinoma, for early and better management of patients with bladder tumor.

Keywords: Micropapillary; prognosis; urothelial carcinoma; variant

How to cite this article:
Divya K N, Jayashree K. Fine needle aspiration cytology of a case of micropapillary variant of urothelial carcinoma of bladder. J Cytol 2011;28:127-30

How to cite this URL:
Divya K N, Jayashree K. Fine needle aspiration cytology of a case of micropapillary variant of urothelial carcinoma of bladder. J Cytol [serial online] 2011 [cited 2022 Dec 1];28:127-30. Available from:

   Introduction Top

Urothelial lesions have a pronounced ability for divergent differentiation. It is important for the pathologists to be aware of this potential for multidirectional differentiation as it has diagnostic, therapeutic and prognostic implications. [1] The cytology of one of the many faces of urothelial carcinomas, the micropapillary variant, is described in this study. The purpose of this report is to underscore the importance of recognition of micropapillary variant of urothelial carcinoma, an aggressive tumor with deceptive morphology. Diagnosing this variant by cytology is important in distinguishing this lesion from the more indolent urothelial carcinoma. [2]

   Case Report Top

A 65-year-old man presented with gross painless hematuria. The patient was a chronic smoker. The ultrasound examination of the abdomen showed a hypoechoic mass in the urinary bladder. No other lesions were seen in abdominopelvic region and the chest radiograph was within normal limits. Renal function tests were within normal limits. The routine urine analysis showed plenty of red blood cells and few pus cells per high-power field and traces of albumin. Cystoscopy revealed a solid growth in the posterolateral wall of the bladder. Ultrasound-guided fine needle aspiration cytology of the bladder mass was performed. The smears were stained with hematoxylin and eosin (H and E) stain.

Microscopically, the highly cellular smears showed many clusters and some papillary fronds with central fibrovascular core. The columnar cells had dense moderate cytoplasm and oval hyperchromatic nuclei [Figure 1]. Occasional cells showed pleomorphic nuclei with prominent nucleoli. Many tightly cohesive micropapillary clusters were seen [Figure 2]. These micropapillae lacked central fibrovascular core. An extracellular myxoid stromal substance was present in the background. A cytological diagnosis of urothelial carcinoma with micropapillary component was made.
Figure 1: Smears showing urothelial component (H and E, × 400)

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Figure 2: Smears showing micropapillary component (H and E, × 400)

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The patient underwent transurethral resection of the tumor and the fragments were subjected to histopathological examination. The paraffin-embedded, H and E-stained sections showed a high-grade urothelial carcinoma infiltrating the muscularis mucosa, admixed with micropapillary component. The extent of micropapillary component was moderate, accounting to 40% of the tumor specimen. The urothelial component consisted of pleomorphic cells showing nuclear clustering around central fibrovascular core. They had eccentric nuclei with coarsely granular chromatin. The micropapillary component consisted of small nests of tumor cells residing within the lacunae [Figure 3]. An abundant myxoid matrix was present in the background. The diagnosis of micropapillary variant of urothelial carcinoma was confirmed.
Figure 3: Section showing nests of tumor cells in lacunae (H and E, × 400)

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   Discussion Top

The spectrum of bladder carcinoma is quiet diverse, with urothelial carcinoma making up the vast majority of cases. The recent World Health Organization classification has recognized 13 variant morphologies of bladder tumors, including those variants which have clinical significance like micropapillary, sarcomatoid, small cell and lymphoepithelioma-like carcinoma. [1] Collectively, the presence of varied morphologies is a poor prognostic indicator. Micropapillary urothelial carcinoma was first described in 1994 by Amin et al.[3] as an aggressive variant of urothelial carcinoma, with distinctive histological features reminiscent of ovarian papillary serous tumor. This rare variant comprises 0.6 to 1% of urothelial carcinoma and shows definite male predominance (male to female ratio is 5:1), which is higher than in the conventional urothelial carcinoma (3 : 1). More than 95% of micropapillary urothelial carcinomas are muscle invasive compared with 45% of conventional urothelial carcinomas. Immunohistochemical profile (CK 7 and CK 20 positive) is similar to that of urothelial carcinoma. In addition, membranous staining of CA 125 has been reported at a higher frequency in micropapillary variant. [3]

Micropapillary variant is often associated with conventional urothelial carcinoma. The tumors are stratified on the extent of micropapillary component into focal (less than 10%), moderate (10 to 50%) and extensive (more than 50%). Cases of extensive micropapillary component are associated with advanced stage of disease. [4]

Fine needle aspiration cytology shows the micropapillary component as tightly cohesive tumor clusters and morules. The urine specimen shows tiny micropapillary clusters admixed with single malignant urothelial cells. [2] Histologically, it is characterized by the following five morphologic features: (i) a noninvasive filiform architecture and an invasive arrangement of small nests or balls of tumor cells; (ii) psammoma bodies, a feature of papillary serous carcinoma of ovary are conspicuously absent; (iii) the tumor cells are predominantly aggregated in lacunae; (iv) it is associated with high nuclear grade and (v) more than half of the cases present with lymphovascular invasion. [3]

The differential diagnosis includes metastatic micropapillary carcinoma of lung, ovary and breast. Clinical and radiological correlation is needed to rule out primary tumors at these sites. Identification of an admixed urothelial carcinoma or immunohistochemical support in the form of CK 7, CK 20 and uroplakin III positivity may be needed in doubtful cases. The primary adenocarcinoma of bladder has greater variability in its acinar size and shape, in contrast to the typical uniform appearance of micropapillary component of urothelial carcinoma. [5]

There are several important reasons for recognizing micropapillary variant of urothelial carcinoma, which are as follows:

  1. These tumors are high grade and high stage and are associated with vascular invasion.
  2. The micropapillary variant has a higher DNA index than conventional carcinoma.
  3. Presence of micropapillary component in metastatic sites forces the pathologist to consider the possibility of urothelial carcinoma.
  4. The high association of this variant with muscle-invasive disease. [1]
The majority of these tumors (90%) present with at least stage pT1 disease at the time of diagnosis and have a 5-year and 10- year survival rate of 54 and 27%, respectively. [6] The patients are at a high risk for treatment failure because of drug resistance to standard chemotherapeutic agents. Intravesical Bacillus Calmette-Guerin therapy is ineffective in these patients, and radical cystectomy should be the treatment of choice. [7] The poor outcome underscores the need for an early and accurate diagnosis by cytological examination.

   Conclusion Top

The accurate recognition of micropapillary variant of urothelial carcinoma is of paramount importance due to the diagnostic dilemma associated with it as well as prognostic and therapeutic implications, and fine needle aspiration cytology is a useful tool for an early diagnosis of this variant.

   References Top

1.Amin MB. Histological variants of urothelial carcinoma: Diagnostic, therapeutic and prognostic implications. Mod Pathol 2009;22 Suppl 2:S96-S118.  Back to cited text no. 1
2.Ylagan LR, Humphrey PA. Micropapillary variant of transitional cell carcinoma of the urinary bladder: a report of three cases with cytologic diagnosis in urine specimens. Acta Cytol 2001;45:599-604.  Back to cited text no. 2
3.Amin MB, Ro JY, el-Sharkawy T, Lee KM, Troncoso P, Silva EG, et al. Micropapillary variant of transitional cell carcinoma of the urinary bladder-histologic pattern resembling ovarian papillary serous carcinoma. Am J Surg Pathol 1994;18:1224-32.  Back to cited text no. 3
4.Samaratunga H, Khoo K. Micropapillary variant of urothelial carcinoma of the urinary bladder: a clinicopathological and immunohistochemical study. Histopathology 2004;45:55-64.  Back to cited text no. 4
5.Shah VB, Rupani AB, Pathak HR. Micropapillary carcinoma of urinary bladder. Indian J Pathol Microbiol 2008;51:308.  Back to cited text no. 5
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6.Kamat AM, Dinney CP, Gee JR, Grossman HB, Siefker-Radtke AO, Tamboli P. Micropapillary bladder cancer. Cancer 2007;100:62-7.  Back to cited text no. 6
7.Nigwakar P, Amin MB. Many faces of urothelial carcinoma: an update with an emphasis on recently described variants. Adv Anat Pathol 2008;15:218-33.  Back to cited text no. 7

Correspondence Address:
K N Divya
Department of Pathology, Medical College (VIMS), Bellary - 583 104, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0970-9371.83472

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  [Figure 1], [Figure 2], [Figure 3]

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