Malacoplakia of the tongue: a case report and clinicopathologic review of 6 cases

BackgroundExtra-urogenital tract malacoplakia is uncommon, with tongue malacoplakia being exceptionally rare. The nonspecific clinical presentation and variable histologic patterns can make recognition of this lesion and separation from other lesions challenging. There are only a few reported cases in the English literature.Materials and methodsFive case reports of tongue malacoplakia were compiled from the literature (MedLine 1960–2008) and integrated with this case report.ResultsThe patients included 4 males and 2 females, ranging in age from 9 to 98 years (mean, 64 years). Patients presented with difficulty swallowing, foreign body sensation, a mass lesion, or referred pain (neck or ear). Symptoms were present from a few days up to 18 months. The base of the tongue was the most frequent site, although midline tongue and half of the tongue were also affected. Radiographic studies demonstrated a mass, with a single lesion showing positron emission tomography positivity. Two patients had previous cancers (prostate and colorectal; larynx). This case report was a farm hand for horses, with gram-negative rods, suggestive of Rhodococcus equi identified. The lesions were 1 to 2 cm in greatest dimension. Histologically, there is pseudoepitheliomatous hyperplasia or ulceration with a heavy acute and chronic inflammatory infiltrate. The subepithelial spaces are completely filled with eosinophilic histiocytes, most of which contain granular material in their cytoplasm. Well-formed, blue, calcific bodies are noted, a few showing a “targetoid appearance” and concentric lamination. These Michaelis-Gutmann bodies are positive with von Kossa, iron, and periodic acid-Schiff stains. These findings support a diagnosis of malacoplakia. The differential diagnosis includes granular cell tumor, poorly differentiated carcinoma, and Langerhans histiocytosis. Patients are managed with antibiotic therapy and excision.ConclusionsTongue malacoplakia is rare, often presenting as a mass lesion. Histologic recognition of this abnormal phagocytic disorder will prevent potentially disfiguring surgery.