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Morphogenesis of Michaelis-Gutmann bodies in cerebral malacoplakia. An ultrastructural study
1Department of Pathology, Henry Ford Hospital, Detroit, MI 48202.
Abstract:
Malacoplakia was found in the brain biopsy specimen from the wall of a cystic lesion in a 4-month-old girl. Ultrastructural study of the Michaelis-Gutmann bodies revealed that the initial stage of calcification appeared to be the deposit of needle-shaped apatite crystals within intracytoplasmic membrane-bound vesicles of histiocytes. Accumulation of apatite crystals and coalescense of calcified vesicles resulted in the formation of large laminated calcospherules. Extracellular Michaelis-Gutmann bodies and apatite crystal-containing matrix vesicles were also noted. Calcified vesicles and the Michaelis-Gutmann bodies were not observed in the phagolysosomes. Bacteria and viral particles were not identified. These findings suggest that matrix and intracytoplasmic membrane-bound vesicles play an important role in the initial stage of the formation of Michaelis-Gutmann bodies and that a mechanism other than bacterial or viral infection may be involved in cerebral malacoplakia.
Insights
Cerebral malacoplakia in an infant involves Michaelis-Gutmann bodies forming via apatite crystal deposits in histiocyte vesicles. This suggests non-bacterial mechanisms may cause this rare brain condition.
Area of Science:
- Neuropathology
- Cell Biology
- Mineralization
Background:
- Malacoplakia is a rare inflammatory condition characterized by the presence of Michaelis-Gutmann bodies.
- Cerebral involvement is exceptionally uncommon, particularly in infants.
Observation:
- A brain biopsy from a 4-month-old girl revealed malacoplakia within a cystic lesion.
- Ultrastructural analysis of Michaelis-Gutmann bodies was performed.
Findings:
- Initial calcification involved needle-shaped apatite crystals within intracytoplasmic vesicles of histiocytes.
- Accumulation and coalescence of these vesicles formed large, laminated calcospherules.
- Extracellular Michaelis-Gutmann bodies and matrix vesicles containing apatite crystals were observed.
- Michaelis-Gutmann bodies and calcified vesicles were absent in phagolysosomes.
- No bacteria or viral particles were identified.
Implications:
- Intracytoplasmic and matrix vesicles are crucial in the early formation of Michaelis-Gutmann bodies.
- The pathogenesis of cerebral malacoplakia may involve mechanisms independent of bacterial or viral infection.