A rare case of unilateral tonsillolithiasis

Clinical History

An eighty-seven-year-old healthy ex-smoker was referred via a general practitioner because of suspected tonsillar cancer. The patient sought medical help due to 3 weeks of sensation of roughness in the left side of the throat, light odonyphagia, but no otalgia. He reported 3 kilos weight loss during the last 2 months.

Imaging Findings

Contrast enhanced CT of the neck was performed using a Philips 64-slice scanner with 100 ml Omnipaque 350 mg/ml administred intravenously. The images revealed a large calcification at the site of the left palatine tonsilla surrounded by inhomogeneously contrast enhancing soft tissue (Fig. 1, 2 and 3). The enhancing area measured 22 x 13 x 24 mm (AP/RL/CC). At a few slices the enhancement appeared ring-like imitating an abscess, but with no hypodense centre (Fig. 1 and 3). Based on the inhomogeneous appearance of the tissue with the central calcification and the clinical history of former smoking, the area was suspected of malignancy and the patient was referred for surgery.

Discussion

Giant tonsilloliths are rare dystrophic calcifications that develop in enlarged tonsillar crypts within the substance of the tonsil or around it [1]. Tonsilloliths consist of calcium salts e.g. hydroxyapatite, calcium carbonate apatite, oxalates and magnesium salts as well as several anaerobic bacteria. Gradual enlargement of the concretion occurs due to deposition of inorganic salts from saliva [2, 3]. The concretions vary in size, shape and colour. There is no significant gender difference and it has been described in patients ranging from 10 to 77 years of age, the mean age of occurrence being 46. The exact pathogenesis is not known. It has been suggested that fibrosis near the openings of the tonsillar crypts, due to repeated inflammation, may cause accumulation of bacterial and epithelial debris which form retention cysts that subsequently calcify [4, 5].

Small concretions are common and asymptomatic [6]. 8-9% of the patients can be asymptomatic, aged in the range of 20-68 [4, 6, 7, 8]. They can occur bilaterally and are usually a few millimetres [9, 10, 11]. Prevalence of palatine tonsilloliths in radiological studies varies considerably, from 16% [9] to 46.1% [11]. Large tonsilloliths are usually unilateral and may cause throat pain, swelling in the tonsillar region, odynophagia, dysphagia, otalgia, halitosis, foreign body sensation and irritable cough [4]. The condition may clinically mimic abscesses and neoplasm and cause diagnostic difficulties due to the rarity [1]. The lesion is located in an area difficult to access and palpate. The palpable part can be hard depending on the degree of calcification [2]. Panoramic radiography reveals radiopaque shadows over the ascending rami of the mandible. Computed tomography (CT) can determine the exact location to distinguish tonsilloliths from other anatomical/pathological structures [1-5, 7, 9].

In our case CT revealed not only a calcification, but also contrast enhancement within the tonsil. Because of the potential malignancy suspected from the clinical presentation and this CT appearance the patient was offered left tonsillectomy.

Histologic examination of the tonsillolith showed necrotic, lamellated material and calcification. No vital tissue. The tonsil was lined by well-differentiated squamous epithelium and underlying lymphoid tissue with normal germinal centres. No dysplasia or malignancy.
In general tonsilloliths are monitored, but they can be removed by either curettage, local excision/incision or performing a tonsillectomy. Complications due to tonsilloliths are uncommon.

Rare unilateral and dystrophic calcifications in the tonsillar fossa can be difficult to diagnose when suspicion of cancer is raised. A thorough patient history and clinical examination will not necessarily suffice. Proper CT description is important in determining the correct diagnosis and treatment accordingly.

Differential Diagnosis List

Final Diagnosis

Tonsillolithiasis

URL:	https://www.eurorad.org/case/11347
DOI:	10.1594/EURORAD/CASE.11347
ISSN:	1563-4086