Histoplasma-associated inflammatory pseudotumour of the kidney mimicking renal carcinoma

In this case report, we describe an unusual case of mycobacterial associated inflammatory pseudotumor that occurred in a patient with a previous history of cocaine abuse. We discuss inflammatory pseudotumor (IPT) in general and emphasize the rare entity where an associated mycobacterial infection is seen. The histogenesis is not yet completely understood. The lesion can pose challenges for practicing pathologists and a misdiagnosis of malignancy can occur at multiple facets. A discussion about the differential diagnosis and clues to make the distinction is presented. In addition to spindle cell proliferation, the presence of a background of mixed inflammatory cell infiltrate and foamy macrophages are clues to make the diagnosis. In the case of mycobacteria associated IPT, Acid Fast Bacilli (AFB) stains will easily highlight the organisms confirming the diagnosis.

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“…Many cases have been reported demonstrating their presence in various other body sites associated with IPT [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Myocbacterium-Avium Intracellulare Associated Inflammatory Pseudotumor of the Anterior Nasal Cavity

Ilyas

Youssef

Chaudhary

et al. 2011

Head and Neck Pathol

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“…The microscopic differential diagnoses and histopathological challenges confronting a histopathologist appraising co‐lesional AIDS‐KS and granulomas are multifaceted, because the granulomas may be fortuitous and unrelated to, or induced by, KS or the HIV/AIDS background (Table 2). 1,26,34–44 Although co‐lesional infections, including M. tuberculosis infection, may induce granulomas with necrobiotic, sarcoidal, necrotizing and suppurative histomorphology, 1,25,34,35 only caseative necrotizing and sarcoidal granulomas were evident in the present study. Characteristic histomorphologic features, ‘infective’ stains and immunohistochemical and molecular investigations are critical to the confirmation of the etiologic agent.…”

Section: Discussionmentioning

confidence: 53%

“…In contrast to that described in MOTT IPTs, the granulomas in the present study were discrete, well formed and paucibacillary. Infective stains, microbiological culture and molecular investigations are also critical in distinguishing co‐lesional KS and M. tuberculosis infection from Cryptococcus neoformans and Histoplasma capsulatum induced IPTs 36,38 …”

Section: Discussionmentioning

confidence: 99%

Granulomas in acquired immunodeficiency syndrome‐associated cutaneous Kaposi sarcoma: evidence for a role for Mycobacterium tuberculosis

et al. 2010

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“…Microbial infections and their immune suppression status may play important roles in IMT occurrences; for example, viral DNA sequences are found in the spindle cells of IMT, and there is a higher incidence in individuals with immunosuppression conditions or who are taking corticosteroid treatment. 8 – 11 Trauma and chronic hepatitis B infection are also thought to play a role in tumorigenesis. 12 ALK gene rearrangement has been confirmed in some IMTs, suggesting that ALK rearrangement is correlated with tumor progression.…”

Section: Discussionmentioning

confidence: 99%

A Renal Inflammatory Myofibroblastic Tumor Similar to Cystic Renal Cell Carcinoma

Liang

2015

Medicine

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We describe and analyze the clinical course and imaging findings of a case of a renal inflammatory myofibroblastic tumor (IMT) that is similar to cystic renal cell carcinoma.“Solitary cysts” on the left kidney were found during a health examination of a 60-year-old female. The patient also had hypertension. She had undergone surgeries twice for limb trauma fracture and had no definite record of hepatitis. There was no tenderness with percussion of the kidney area or edema in the lower extremity. The renal function results, including serum creatinine, blood urea nitrogen, and blood urea, were within the normal range. No gross hematuria or microscopic hematuria was found. An 8.7 cm × 9.2 cm mixed echogenic mass at the upper pole of the left kidney was observed with ultrasound, the majority of which was an anechoic mass that was slightly protruding from the renal capsule and had well-circumscribed borders. After a bolus injection of an ultrasound contrast agent, the mass had rapid enhancement with fast fading. An approximately 9.4 cm × 10.1 cm round-like cyst lesion at the upper pole of the left kidney was revealed by computed tomography (CT) examination of the abdomen; it had edge finishing with well-circumscribed borders. The upper inner wall of the lesion was thick with crescentic soft tissue. The solid content had gradual enhancement on enhanced CT scans. A kidney tumor was considered based on the CT findings.Based on the preoperative examination, the left renal cystic masses were resected. Intraoperative frozen sections were used to further clarify the nature of the lesion, and no significant malignant cells were observed; therefore, the kidney was not removed. The pathological diagnosis was renal IMT. After surgery, the patient recovered and did not have recurrence or metastasis over the course of long-term follow-up.CT images of our patient with renal cystic disease are categorized as Fuhrman grade IV and typically indicate the presence of malignant lesions. However, gradual enhancement of the solid content in our case is different from typical cystic renal cell carcinoma. The nature of the lesion was further identified using intraoperative frozen sections, which helped avoid unnecessary nephrectomy.

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Histoplasma-associated inflammatory pseudotumour of the kidney mimicking renal carcinoma

Cited by 10 publications

References 15 publications

Myocbacterium-Avium Intracellulare Associated Inflammatory Pseudotumor of the Anterior Nasal Cavity

Myocbacterium-Avium Intracellulare Associated Inflammatory Pseudotumor of the Anterior Nasal Cavity

Granulomas in acquired immunodeficiency syndrome‐associated cutaneous Kaposi sarcoma: evidence for a role for Mycobacterium tuberculosis

A Renal Inflammatory Myofibroblastic Tumor Similar to Cystic Renal Cell Carcinoma

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