Case series of pediatric mediastinal granuloma related to histoplasmosis

Mediastinal granuloma (MG) is a postinfectious complication of histoplasmosis that remains a rare diagnosis in the pediatric literature. This case series presents a well phenotyped population to further characterize this disease process.

Thirty cases of MG in children under 21 years-of-age presenting over a 16-year period were retrospectively analyzed.

Seventy-five percent of patients presented with respiratory symptoms. Histoplasma antigen was negative in 90%. Histoplasma antibody was positive in 100%. Fine needle aspirates were positive for histoplasma in 31% whereas excisional biopsy was positive in 71%. Bronchoalveolar lavage (BAL) was negative for histoplasma in all cases where performed. Computed tomography revealed 53% of MGs were right paratracheal, 60% had internal calcifications, and 23% had splenic calcifications. Sixteen patients (53%) were managed with medical therapies only, with 7 (44%) treated with steroids and antifungals and 7 (44%) with antifungals alone. The remaining 14 patients (47%) underwent surgical excision and 9 were also treated with antifungals (64%). Bronchial compression was the most common comorbidity within the medically managed only group whereas vascular compression and fistulation were most common within the surgically managed group.

Respiratory symptoms should raise suspicion for MG. Diagnostic evidence of MG includes positive histoplasma serologies, right paratracheal location, internal calcifications, and splenic calcifications. Bronchoscopy, BAL and needle biopsies provide minimal diagnostic benefit. Antifungals are used in the majority of cases, whereas steroids are used most often in non-surgically managed patients with airway compression. Indications for surgical resection are less defined, but include vascular compression and fistulation unresponsive to medical treatment.