Laryngeal actinomycosis with dysplasia in a young male with a recurrent laryngeal polyp

Introduction

Actinomycosis is a disease caused predominantly by Actinomyces israelii predominantly. This is an anaerobic, gram-positive organism which is a normal commensal of the oral cavity. Actinomycosis is a chronic, suppurative infection which may manifest in one of three forms: cervicofacial (60%), abdomino-pelvic (22%) or thoracic (15%). ¹ Actinomycosis less frequently affects the larynx, nasopharynx, oropharynx, laryngopharynx and trachea. On extensive search of literature, only around 25 cases of laryngeal actinomycosis have been reported to date.^1–13

We report a rare case of laryngeal actinomycosis associated with focal dysplasia in a 28-year-old man with a complaint of hoarseness of voice with recurrent laryngeal polyp.

Case report

A 28-year-old man presented to the ENT clinic with the complaint of change in voice and hoarseness for the previous 12 months. There was a history of micro-laryngoscopic excision of a polyp seven months previously. On histopathology, it was compatible with a vocal cord polyp without any evidence of dysplasia or malignancy. There was no history of fever, breathlessness, dysphagia, weight loss, diabetes mellitus, tuberculosis or dental caries. The patient was a non-smoker and there was no history of vocal abuse.

General physical examination was normal. Indirect laryngoscopy revealed a polyp obscuring the laryngeal inlet. The origin of the polyp could not be visualised. Nose, ear and throat examination was within normal limits. Investigations revealed: haemoglobin, 13.8 g/dL; total leucocyte count, 11,300/mm³ with 73% neutrophils; platelets, 3.42 lakhs/mm³. Liver and kidney function tests were within normal limits. Serology for HIV, HBsAg and HCV was negative. A chest radiograph revealed borderline cardiomegaly, however, bilateral lung fields did not show any active parenchymal pathology.

Microlaryngoscopic excision was performed under general anaesthesia. A polypoidal mass was observed at the anterior commissure with overlying slough. The mass was excised and sent for histopathology. Haematoxylin and eosin (H&E) stained sections showed multiple polypoidal tissue lined by acanthotic stratified squamous cells. At one focus, the stratified squamous epithelium showed loss of polarity, nuclear enlargement and anisonucleosis. However, even on extensive serial sectioning, there was no evidence of invasion. Areas of necrosis alongwith colonies of Actinomyces sp were found (Figure 1). These colonies were positive on Gram stain and Gomori’s methanamine silver (black colonies) (Figure 2), but they were not acid fast. A diagnosis of focal dysplasia associated with actinomycosis was suggested. The patient was given amoxicillin therapy and was kept on closely followed. He did not have any recurrent lesions at one year following biopsy. OPEN IN VIEWER

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Figure 2.

(a) Photomicrograph showing filamentous colonies of Actinomyces sp. (H&E, 400×), (b) photomicrograph showing black colonies on Gomori’s methanamine silver stain (400×).

Discussion

Cervicofacial actinomycosis (CFA) is a rare chronic infection which is usually associated with poor dental hygiene, immunosuppressed status and oro-maxillofacial trauma thereby leading to direct and progressive mucosal invasion by the bacteria.^7,10 The differential diagnoses includes carcinoma, abscess, congenital anomalies, tuberculosis, fungal disease and osteomyelitis. Therefore, CFA has been referred to as a ‘great masquerader’ among diseases of the head and neck. ⁹

Actinomycosis of the larynx is an extremely rare condition; most of the reported cases occurred in patients who either had a history of laryngeal carcinoma and radiotherapy or presented with an ulcer which resembled relapse of laryngeal cancer. None of the patients presented with an abscess or sinus formation.

Our case was of an immunocompetent young man, a non-smoker, with hoarseness of voice and only history of a recurrent laryngeal polyp. The prior surgical excision of a polyp could be the reason for disruption of normal mucosa and eruption of Actinomyces sp. The diagnosis was made on histopathological examination of the operative specimen. Microscopic examination has been regarded by several authors as the quickest and the most sensitive means of diagnosis. ² However, culture studies are needed for accurate diagnosis and identification of the causative organism. The laboratory must be notified if actinomycosis is suspected as it is a strict anaerobe and culture must be maintained for at least two weeks.

Actinomycotic granules contain delicate, branched filaments which are gram-positive, non-acid fast and sometimes beaded. They are deep bluish purple and gram stain can demonstrate them well. Both histopathology and culture are required for a definitive diagnosis as other filamentous bacteria such as nocardia can also form granules similar to actinomycosis. Moreover, nocardia sp are not invariably acid fast. ¹

The treatment of choice is a prolonged course of penicillin or amoxycillin therapy. We present this case on account of the rarity of this condition as well as the unusual presentation with dysplasia unlike most of the cases in the literature with a history of carcinoma larynx.