Clinicopathologic study of satellite lesions in nontuberculous mycobacterial keratitis

Multifocal stromal infiltrates or "satellite lesions" have been considered a characteristic feature of fungal keratitis. We examined two patients with nontuberculous mycobacterial keratitis who clinically presented with satellite lesions. The keratitis consisted of multifocal stromal infiltrates with indistinct white and fluffy margins. Both patients received topical fortified amikacin therapy with poor response. Lamellar keratectomy or penetrating keratoplasty was performed, respectively, in the two patients because of progressive stromal thinning and enlarging satellite lesions. Histopathologically, the main lesions consisted of dense infiltration of inflammatory cells with numerous acid-fast bacilli, while the satellite lesions were composed chiefly of inflammatory cells with fewer mycobacteria. Besides fungal keratitis, nontuberculous mycobacterial keratitis should also be considered when satellite lesions are present.