Malignant masquerade: A case report of urachal malakoplakia disguised as urachal tumor

Abstract

Malakoplakia is a rare inflammatory disease that predominantly affects the genitourinary tract, with the urinary bladder being the most commonly involved site. Although its exact pathogenesis remains unknown, it is well-established that the condition is associated with chronic urinary tract infections and immunosuppression. Its presentation often poses a significant diagnostic challenge, as it can closely mimic malignancy. We report a case of a 55-year-old female who presented with lower urinary tract symptom with a palpable hypogastric mass, imaging suspected urachal tumor. A partial cystectomy was performed, which histology confirmed the diagnostic of Urachal Malakoplakia.

Highlights

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Malakoplakia is a rare granulomatous disease that mimics malignancy.
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It results from defective phagocytosis, leading to bacterial accumulation.
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The genitourinary tract, especially the bladder, is the most affected site.
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Diagnosis relies on histopathology, showing Michaelis-Gutmann bodies.
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Treatment includes antibiotics, surgery, and immune-modulating therapies.

1 Introduction

Malakoplakia is an unusual granulomatous inflammatory disease of uncertain etiology, first identified in 1902 by Michaelis and Gutmann. This rare disease is more frequently observed in immunocompromised and elderly patients. While it can affect various organs, it was initially described in and predominantly involves the genitourinary tract, with the bladder being the most commonly affected site. While malakoplakia is a benign condition, it often mimics a malignant neoplasm, particularly when a mass-like lesion is present. The gold standard for the diagnosis and treatment of malakoplakia has not yet been established. We report an exceptionally rare case of urachal malakoplakia without bladder involvement. As far as we know, this represents the first reported case of its kind in our country. A comprehensive literature review revealed very few similar cases reported elsewhere.

2 Case presentation

A 55-year-old female, with a history of diabetes for 3 years, hypercholesterolemia on statin therapy for 2 years, presented to the urology department with dysuria, pollakiuria, urinary urgency and suprapubic pain with a palpable mass in the hypogastric region, evolving in a context of weight loss and fatigue over the past few months.

On physical examination, palpation of the lower abdomen revealed a firm, tender and painless hypogastric mass. Otherwise, there was no pain in lumbar fossae.

The ultrasound showed a heterogeneous hypoechoic mass poorly defined, in contact with the anterior bladder wall, specifically in the area of the urachus, measuring 52 × 35mm ( Fig. 1 ).

We completed investigations by Uro-CT which confirmed the presence of a heterogeneous mass on the anterior bladder wall with a thickened and irregular wall enhancing after contrast injection, containing heterogeneous liquid, measuring 64 × 58mm, with heterogeneity in the surrounding tissues, likely due to extension or involvement of adjacent fat, without iliac or lumbar aortic lymph nodes ( Fig. 2 ).

Due to the mass effect exerted by the mass and the difficulty in orienting the diagnosis, a pelvic MRI was requested to precisely detect the presence of an endoluminal growth and any potential infiltration of the bladder wall, which showed a supravesical cystic formation, along the midline, behind the muscular wall, restricting diffusion, with a thickened wall enhanced after injection, measuring 45×40 × 32mm, appearing suspicious, exerting a mass effect on the bladder dome without endoluminal growth ( Fig. 3 ).

Cystoscopy revealed no obvious intraluminal growth, with a protruding appearance of the bladder mucosa at the level of the dome ( Fig. 4 ) with hyperemia. The biopsy revealed features of cystitis with no evidence of malignancy.