Solitary Reticulohistiocytoma of the External Auditory Canal: A Case Report

Introduction: Solitary reticulohistiocytoma (SRH) is a rare condition that presents as a brownish solitary nodule, measuring less than 1 cm. It affects the head and neck regions of middle-aged individuals and is microscopically characterized by an infiltrate of histiocytes and giant cells with an extensive cytoplasm with an aspect of "ground glass." It is not related with systemic diseases. When it appears as multiple lesions, it may be confused with multicentric reticulohistiocytosis, which can be malign.

Objectives: This study reports a rare case of a young patient diagnosed with SRH, calling attention to this disease that affects mainly the head and neck.

Resumed Report: A 24-year-old female patient (F. L. L.) complained of discomfort in her right ear for 45 days after manipulation due to itching. She developed aural fullness and discrete bloody otorrhea. The otoscopy of the right ear revealed a solid tumoral lesion obstructing almost completely the external auditory canal. She reported immediate hearing improvement with the manipulation of the lesion. She underwent an excision by an endomeatal route under local anesthesia. The anatomopathologic study revealed a reticulohistiocytoma. She did not present any other similar lesion. There was no recurrence in the postoperative follow-up and the dermatological evaluation conducted showed that there were no other similar lesions in other areas, setting the case as SRH.

Conclusion: The prognosis of SRH is good, since there is no associated systemic disease, and following surgical removal there is little or no tendency to relapse. However, early diagnosis is very important due to the severity of some of the differential diagnoses.