대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Pulmonary malakoplakia

Radiologic Findings

Fig 1. A serial Chest PA reveals a pleural-based mass-like opacity with a calcified wall, suggestive of findings consistent with chronic empyema. Another mass-like opacity is also noted at the medial side of the presumed chronic empyema, demonstrating an increase in size.

Fig 2-5. CT scans reveal a 5.2cm irregular, multi-septated cystic mass adjacent to chronic empyema. The calcified wall of the chronic empyema is intact, and the solid portion of the mass shows mild enhancement and hypermetabolism.

Brief Review

Pulmonary malakoplakia is a very rare disease that is more frequently found in immunocompromised patients than in immunocompetent individuals. Only 38 cases of pulmonary malakoplakia have been documented in the English literature.
The majority of malakoplakia (58-80%) involves the genitourinary system. Known risk factors include immunosuppression, alcoholism, poorly controlled diabetes, malignancy and so on.
In pathology, the presence of Michaelis-Gutmann bodies is a pathognomonic feature of malakoplakia. These are foamy macrophages exhibiting basophilic intracytoplasmic inclusions, which undergo mineralization through the subsequent deposition of calcium and iron associated with lysosome calcification. In genitourinary system, malakoplakia is typically linked to gram-negative bacteria such as Escherichia coli and Klebsiella species. However, pulmonary malakoplakia is most commonly associated with Rhodococcus equi in immunocompromised patients.
Only a few cases of pulmonary malakoplakia have been reported in immunocompetent patients, with some cases being associated with chronic empyema, as seen in this case.

References

1. Narwani, Pooja, et al. "Malakoplakia presenting as pleuropulmonary masses: a rare clinical, radiological and histopathological diagnosis." Radiology Case Reports 16.12 (2021): 3859-3863.
2. Mandal, P., W. A. Wallace, and K. M. Skwarski. "Pulmonary malakoplakia: a rare presentation mimicking extensive stage IV lung cancer." European Respiratory Journal 38.4 (2011): 983-985.
3. Gupta, Kumud, and Sapna Thakur. "Pulmonary malakoplakia: a report of two cases." Indian Journal of Pathology and Microbiology 54.1 (2011): 133-135.
4. Corr

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