Cystitis follicularis in bladder washings: report of two cases and review of the literature

An Approach to Nonurothelial Malignancies of the Urinary Bladder in Urine Cytology

Urine cytology is an economical and convenient method of triaging patients who present with urinary symptoms as well as surveying those who have previously been diagnosed with urothelial carcinoma for recurrent or persistent disease. While the vast majority of malignancies diagnosed in urine cytology are urothelial carcinomas, it is important to recognize nonurothelial elements to inform patient prognosis and raise the possibility of involvement by a urothelial carcinoma variant, nonurothelial malignancy of the bladder, or a nonbladder primary, which may alter patient management pathways. As such, becoming familiar with morphologic features of nonurothelial malignancies in urine cytology as well as their related clinical risk factors, radiologic and cystoscopic features, differential diagnostic considerations, and the utility and pitfalls of ancillary tests can facilitate optimal patient care.

Cytomorphologic features and differential diagnosis of neoplasms with small cell features in liquid-based urinary tract cytologic specimens

INTRODUCTION

Urinary tract cytology (UTCy) allows the accurate diagnosis of high grade urothelial carcinoma. Rare malignancies characterized by the presence of small cells may be more difficult to recognize, however. The aim of this study was to review our experience with liquid-based (ThinPrep) UTCy specimens showing small atypical cells and characterize their cytomorphology, potential differences from previously reported morphologic features, and discuss their differential diagnostic considerations.

MATERIALS AND METHODS

Among 18,859 UTCy specimens reviewed during a 13-year period (2001-2012), we identified 13 cases corresponding to surgical pathology specimens diagnosed as small cell carcinoma (6), melanoma (3), lymphoma (3), and leukemic involvement of the urinary tract (1). We recorded the original diagnoses made on these cases and 10 cytomorphologic features that could aid in their diagnosis.

RESULTS

We identified 13 cases in UTCy of 7 men and 6 women; 11 of which were diagnosed as positive or suspicious for malignancy. In 8 out of 13 cases (62%) the type of malignancy was correctly reported. Of the 10 recorded features, cellular clustering and nuclear molding were seen only in small cell carcinoma, whereas prominent nucleoli and an inflammatory background or diathesis were noted in lymphoma and melanoma cases. Intracellular pigment and multinucleation were recorded in melanoma cases.

CONCLUSION

The presence of small atypical cells in liquid-based UTCy should raise the suspicion of underlying malignancy involving the urinary tract. Cell clustering, nuclear molding, and hyperchromasia are helpful hints for the diagnosis of small cell carcinoma and the presence of small atypical cells with prominent nucleoli raises the possibility of lymphoma or melanoma.

Hematologic lesions in urine cytology

INTRODUCTION

Bladder infiltration by leukemia or lymphoma is rare and can mimic benign processes such as follicular cystitis (FC).

MATERIALS AND METHODS

Eight benign and malignant hematologic diseases encountered in urine cytology were retrospectively reviewed for clinical, radiographic, and cytologic findings.

RESULTS

There were 2 cases of acute myeloid leukemia, 2 cases of diffuse large B-cell lymphoma, and 4 cases of FC. The most common presenting symptom was hematuria. Imaging findings included echogenic debris within the bladder or an adjacent soft tissue mass in acute myeloid leukemia cases and bladder wall thickening in diffuse large B-cell lymphoma cases. No FC cases had any imaging abnormalities. Cytologic material of the leukemia cases showed numerous myeloid blasts with markedly increased nuclear-to-cytoplasmic ratios, centrally located nuclei, inconspicuous nucleoli, nuclear indentations, and some irregular nuclear membranes. The background showed sparse urothelial cells and histiocytes. Both lymphoma cases showed a discohesive population of atypical large lymphoid cells with irregular nuclear borders and prominent nucleoli. The FC cases had a background lymphoid cell population with a maturation spectrum from small lymphocytes to large lymphoid cells (immunoblasts) and histiocytes including tingible body macrophages. Additionally, there were many mature squamous cells and reactive urothelial cells.

CONCLUSIONS

Bladder leukemia, lymphoma, and FC are infrequently encountered on urine cytology. FC can be distinguished from a hematologic malignancy by the presence of a lymphocytic maturation spectrum and tingible body macrophages. Radiologic abnormalities are associated with malignant processes; however, discrete bladder masses are usually not identified.