SHM Converge Scientific Abstract ePoster Gallery-Bladder Mass With Rapidly Progressive Pelvic Lymphadenopathy: Masquerading as Malignancy

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This case describes a 47-year-old woman with a rapidly enlarging bladder/pelvic mass and progressive pelvic lymphadenopathy, initially concerning for malignancy. She had a year of pelvic pain, night sweats, weight loss, and recurrent pan-susceptible <em>E. coli</em> UTIs. Imaging first showed a 6 cm mass between the bladder and vagina without lymphadenopathy, but over time she developed circumferential bladder-neck involvement and necrotic pelvic nodes. Three biopsies were initially inconclusive, reinforcing the concern for cancer.

Her history included significant immunosuppression from SLE treatment (prednisone, azathioprine, hydroxychloroquine) and prior splenectomy. On admission, she had suprapubic tenderness and a tender ulcerated left inguinal lymph node. Labs showed elevated inflammatory markers, pyuria, hematuria, and persistent <em>E. coli</em> growth in urine. Extensive infectious, autoimmune, and cancer workup was unrevealing.

A key diagnostic step was biopsy of the left inguinal lymph node, which showed sheets of foamy macrophages and neutrophils, with intracellular and extracellular gram-negative rods; stains were negative for mycobacteria and fungi. Universal PCR detected <em>E. coli</em> DNA. A prior biopsy had shown Michaelis-Gutmann bodies, and after multidisciplinary review of pathology and imaging, the final diagnosis was malakoplakia.

Malakoplakia is a rare chronic inflammatory condition caused by impaired macrophage killing of bacteria, often in immunocompromised patients. It most commonly affects the genitourinary tract and is frequently associated with <em>E. coli</em>. Treatment centers on prolonged antibiotics with good intracellular penetration (such as fluoroquinolones), reduction of immunosuppression when possible, and surgery only if needed. In this patient, ciprofloxacin and vitamin C were started, azathioprine was stopped, and prednisone was tapered. Her pain and lymphadenopathy resolved, and follow-up cystoscopy showed normal bladder mucosa. The case highlights the importance of avoiding anchoring bias when a presumed malignancy does not fit the pathology.

Asset Subtitle

Anand R. Habib

Meta Tag

Author List Anand R. Habib, Nancy Choi

Category Clinical Vignettes

Concept Malacoplakia

Concept Bladder Mass

Concept Immunocompromised State

Concept Recurrent Escherichia coli Urinary Tract Infection

Concept Foamy Histiocyte

Distinguished Finalist

Presenter Organization University of California San Francisco

Presenting Author Anand R. Habib

Track Adult

Keywords

malakoplakia

bladder mass

pelvic lymphadenopathy

Escherichia coli

immunosuppression

systemic lupus erythematosus

Michaelis-Gutmann bodies

urinary tract infection

ciprofloxacin

anchoring bias

Malacoplakia

Bladder Mass

Immunocompromised State

Recurrent Escherichia coli Urinary Tract Infection

Foamy Histiocyte