CONCENTRIC RINGS WITHIN A RESTRICTED MASS: A CASE OF COEXISTING CHOLESTEATOMA AND MYCETOMA OF THE TEMPORAL BONE

Introduction: Middle ear cholesteatoma is a well-recognized destructive lesion of the temporal bone. Colonization by a mycetoma arising within a cholesteatoma-generated bony cavity is an exceptionally rare and previously unreported complication. We report the first such case, compounded by three simultaneous complications: ossifying labyrinthitis, lateral semicircular canal fistula, and lateral sinus thrombosis extending to the internal jugular vein.
Case Presentation: A 42-year-old immunocompetent woman with a lifelong history of recurrent otitis media presented with a 3-month left fistulized otomastoiditis. HRCT and multiparametric MRI revealed a voluminous expansile mass centered on the left middle ear causing extensive petromastoid bone destruction. Within the cholesteatoma-generated cavity, a central fungal ball was identified by its characteristic laminated T2 signal pattern and absence of diffusion restriction on diffusion-weighted imaging — contrasting with the peripheral diffusion-restricting cholesteatoma matrix. 
The coexistence of a macroscopic mycetoma within a cholesteatoma-sculpted mastoid cavity has not been previously described. Multiparametric MRI was essential in characterizing this dual pathology, providing non-redundant information to HRCT by resolving the two superimposed lesions, confirming lateral sinus thrombosis, and excluding intracranial extension. This case introduces the concept of cholesteatoma as a biological scaffold for mycetoma formation.
Conclusion: This case illustrates a unique and life-threatening constellation of complications arising from a neglected destructive cholesteatoma. Awareness of this dual pathology and systematic multiparametric imaging evaluation are essential for accurate diagnosis and surgical planning.