The biopsy specimen demonstrated a moderately dense superficial and deep perivascular and perineural lymphocytic and histiocytic infiltrate. Focal, nonnecrotizing granuloma formations were present. A Fite stain showed the presence of acid-fast bacilli within nerve trunks (Figure 3). The bacterial index was 2 (1-10 bacilli per 1 oil-immersion field). The Ziehl-Neelsen stain was negative for acid-fast bacilli.
Painful Plaques and Nodules on the Face, Neck, and Right Wrist of a 51-Year-Old Man—Diagnosis. Arch Dermatol. 2005;141(3):389-394. doi:10.1001/archderm.141.3.390-d