Foreign Body Granuloma Originating From the Lateral Process of Malleus: A Case Series of 19 Children

Objective: A special presentation of foreign body granuloma originating from the lateral process of the malleus (FBGLP) was noted in the absence of a history of foreign body entry into the external auditory canal (EAC). This study reported the clinical features, pathology, and prognosis of patients with FBGLP. Design: Retrospective study. Setting: Shandong Provincial ENT Hospital. Patients: Nineteen pediatric patients (age, 1-10 yr) with FBGLP. Interventions: Clinical data were collected from January 2018 to January 2022. Main outcome measures: Clinicopathologic characteristics of the patients were analyzed. Results: All patients had an acute course, and were within 3 months of ineffective medical treatment. The most common symptoms were suppurative (57.9%) and hemorrhagic (42.1%) otorrhea. FBGLP imaging examinations demonstrated a soft mass blocking the EAC without bone destruction and occasionally concomitant effusion in the middle ear. The most common pathologic findings were foreign body granuloma (94.7%,18/19), granulation tissue (73.7%, 14/19), keratotic precipitate (73.7%, 14/19), calcium deposition (63.2%, 12/19), hair shafts (47.4%, 9/19), cholesterol crystals (5, 26.3%), and hemosiderin (15.8%, 3/19). Foreign body granuloma and granulation tissue showed higher expression levels of CD68 and cleaved caspase-3 than did the normal tympanic mucosa, whereas Ki-67 levels were similarly low in all tissues. The patients were followed up for 3 months to 4 years without recurrence. Conclusion: FBGLP is caused by endogenous foreign particles in the ear. We recommend the trans-external auditory meatus approach for FBGLP surgical excision, as this shows promising outcomes.