Pseudoactinomycotic radiate granules in the maxillary sinus. A case report

Area of Science:

• Pathology
• Histopathology
• Microbiology

Background:

• Pseudoactinomycotic radiate granules (PAMRAGs) are inert structures that resemble true actinomycotic granules.
• These formations are predominantly found in the female reproductive system.
• This study presents a novel case of PAMRAGs identified within the maxillary sinus.

Observation:

• A 74-year-old male patient underwent maxillectomy for a right alveolar ridge carcinoma.
• Histopathological examination of the tumor-free sinus mucosa revealed deposits of mucus, cellular debris, and eosinophilic granules.
• These granules exhibited a radiate pattern with peripheral club-like thickening, were Gram-positive, refractile, and not bi-refringent.

Findings:

• Special stains (Alcian blue, PAS, Ziehl-Neelsen, Grocott, Kongo red) showed specific reactivity patterns.
• Immunohistochemistry revealed strong IgM, moderate IgG, weak IgA, and IgG4, with absent IgD.
• The observed characteristics differentiate these granules from true actinomycosis.

Implications:

• This case represents the first description of pseudoactinomycotic radiate granules in the maxillary sinus.
• PAMRAGs should be considered in the differential diagnosis of maxillary sinus actinomycosis.
• Awareness of this rare entity is crucial for accurate histopathological interpretation.