Case Presentation: A 47-year-old woman with lupus presented with one week of urinary frequency and dysuria. Over the prior year, she had pelvic pain, night sweats, 20 pounds of unintentional weight loss, and eight episodes of pan-susceptible E. coli urinary tract infections (UTIs), each successfully treated. Her chronic medications were prednisone, hydroxychloroquine, and azathioprine.A computed tomography scan (CT) eight months prior to admission found a 6-cm mass between the bladder and vagina. There was no lymphadenopathy. Three separate biopsies were non-diagnostic. Repeat CT one month prior to admission noted growth in the mass and new bilateral pelvic lymphadenopathy. On cystoscopy, the mass did not appear like urothelial cancer. On admission, vital signs were stable. Her exam demonstrated suprapubic tenderness and shotty inguinal lymphadenopathy with a prominent left inguinal node. Labs were notable for an elevated CRP and ESR, urinalysis with pyuria, and urine culture growing E. coli. CT demonstrated progression of the mass and rapidly enlarging, necrotic pelvic lymphadenopathy. Given imaging, there remained concern for malignancy. A left inguinal lymph node biopsy showed inflammatory cells and intracellular gram-negative rods, with E. coli on universal PCR; there were no malignant cells. Integrating biopsy results and the history of recurrent E. coli UTIs, multidisciplinary consensus shifted to a diagnosis of malakoplakia. She was started on ciprofloxacin and vitamin C, her azathioprine was stopped, and prednisone was weaned. At six months post-hospitalization, she had no further UTIs or pelvic pain and had gained 30 pounds. A follow-up CT showed marked reduction in her lymphadenopathy and slight regression of her bladder mass. She continues ciprofloxacin with close monitoring for cystectomy need.
Discussion: Visceral masses with rapidly progressive lymphadenopathy are common problems encountered by hospitalists. While malignancy is a cannot miss diagnosis, this case highlights the challenges of diagnostic uncertainty when biopsies are inconclusive and the cognitive biases that can arise when data suggest a rare diagnosis (malakoplakia) accompanied by an atypical presentation (progressive bulky lymphadenopathy).Malakoplakia is a rare, chronic granulomatous disorder that primarily affects the genitourinary tract. Tissue diagnosis is key as imaging can be variable. Malakoplakia arises from a predisposing immunocompromising condition that impairs macrophage phagolysosome function leading to intra- and extracellular bacterial debris, termed Michaelis-Gutmann bodies. Microbiologically, E. coli is the most common inciting organisms. In this patient’s case, azathioprine and prednisone likely impaired monocyte phagocytic response. Treatment centers on using antibiotics (e.g., fluoroquinolones, TMP-SMX) that achieve high intracellular concentrations and tapering immunosuppressive drugs. Use of cholinergic agonists (e.g. bethanechol) and vitamin C to enhance monocyte chemotaxis and lysosome function is controversial. Recommended antibiotic duration is uncertain but often long-term. Surgical management may be necessary.
Conclusions: Malakoplakia should be on the differential for masses, with or without lymphadenopathy, in the setting of immunocompromised status, biopsy results negative for malignancy, and history of recurrent bacterial infections. Medical management with long term antibiotics can prove effective, sparing patients morbid surgeries.