Pseudoactinomycotic radiate granules in the maxillary sinus. A case report

Pseudoactinomycotic radiate granules are biologically inactive formations simulating true actinomycotic granules. They occur mainly in the female genital tract. Here we describe a previously unreported case of these granules in a maxillary sinus.

A 74-year old man underwent maxillectomy for a carcinoma of the right alveolar ridge. In the tumor-free sinus mucosa, a deposit of condensed mucus, cell debris and eosinophilic granules, surrounded by leukocytes, were seen. These Gram-positive granules were refractile, not bi-refringent and revealed radiate pattern with peripheral club-like thickening. Alcian blue staining was negative, PAS reaction was present at the periphery. Ziehl-Neelsen, Grocott and Kongo red reactions tested negatively. In the mucoid surroundings, strong IgM, moderate IgG, weak IgA and IgG4, but no IgD immunoreactivity was present.

PAMRAGs in the maxillary sinus have not been described so far. Despite their extremely rare occurence, they must be taken into consideration in histopathological differential diagnosis of actinomycosis of that anatomic location.