Urinary bladder malakoplakia mimicking tumor

Case contributed by Yew Shiong Leong
Diagnosis certain

Presentation

Underlying diabetes mellitus, presented with hematuria. Ultrasound showed a urinary bladder mass with resultant obstructive uropathy. Post bilateral nephrostomies insertion.

Patient Data

Age: 65 years
Gender: Female

Marked thickening of the posterior urinary bladder wall with a mass-like appearance and has no clear plane with the uterus and vagina.

Case Discussion

Biopsies of the urinary bladder mass were taken during cystourethroscopy and under transvaginal ultrasound guidance. HPE-proven malakoplakia of the urinary bladder.


HISTOPATHOLOGY REPORT - First Biopsy
Macroscopy
A) It comprises 3 brownish tissue measuring 3x2x1mm & 25x5x3mm. The specimen is entirely submitted in one block.
B) It comprises 2 pieces of brownish tissue measuring 5x4x3mm and 12x4x3mm. The specimen is entirely submitted in one block.

Microscopy
A) Sections show a few fragments of fibrous stromal tissue, displaying areas of crushed artifacts. Some of the better preserved tissues show sheets of histiocytes (Von Hansemann cells) aggregations, surrounded by lymphoid aggregations. These histiocytes (Von Hansenmann cells) show similar cytology as in specimen B. Scattered Michaelis Guttman bodies are noted. The overlying urothelium are unremarkable. No dysplasia or malignancy seen.

B) Sections show two fragments of tissue, displaying sheets of histiocytes aggregation, surrounded by lymphoid aggregation forming reactive germinal centers. These histiocytes (Von Hanseman cells) have round to oval vesicular nuclei with abundant granular polygonal shaped cytoplasm. Nuclear atypia and mitosis is not seen. Scattered Michalis Guttman bodies are seen. The overlying urothelium shsow neutrophils infiltration. No dysplasia, granuloma or malignancy.

Immunohistochemical study show these histiocytes diffusely positive towards CD68.

Diagnosis
Bladder tumor : Malakoplakia, no malignancy



HISTOPATHOLOGY REPORT - Second Biopsy
Macroscopy
Received 3 strips of grayish linear tissue measuring 4,4 & 5mm in length. Submitted entirely in one block. Painted with eosin.

Microscopy
Section show 3 strips of tissue composed of sheets of histiocytes aggregations, surrounded by lymphoid aggregates. These histiocytes has oval vesicular nuclei with small nucleoli and abundant cytoplasm. There are scattered Michaelis Guttman bodies seen. No evidence of malignancy.

Diagnosis
Posterior bladder mass: Malakoplasia. No evidence of malignancy.


The patient was prescribed long-term trimethoprim-sulfamethoxazole (Bactrim). Subsequent CT showed a significant reduction in the size of the mass.

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