A Rare Case of Carcinoma Cuniculatum Involving the Larynx in Association with a Saccular Cyst

Abstract

Carcinoma cuniculatum (CC), a rare, well-differentiated variant of squamous cell carcinoma, is uncommon in head and neck sites but when it does occur is most common in the oral cavity. Here we report a rare case of CC involving the larynx. A 49-year-old man presented with 10 months of worsening hoarseness and, despite multiple biopsies, no diagnosis of malignancy could be established. Eventual partial excision of the lesion and histologic review of prior specimens confirmed the diagnosis of CC. Focally, a transition to respiratory epithelium indicated the presence of an associated saccular cyst. Total laryngectomy was performed and 6 months later the patient is free of disease. Only two prior cases of CC have been reported in the larynx. Diagnosis of CC is challenging given the low grade histologic features and awareness of this entity for both treating physicians and the pathologist is important to reach a diagnosis of malignancy. This case highlights the challenges in diagnosis of CC, especially in unusual locations and when associated with other lesions such as a saccular cyst. Awareness of this rare tumor type combined with close communication between treating clinicians, radiologists and pathologists should allow earlier diagnosis and treatment.

Laryngeal Cysts in Adults: Simplifying Classification and Management

“…Additionally, squamous cell carcinoma of the larynx is well known to be associated with enlarged saccules, with up to 19% of larynges excised for laryngeal carcinoma demonstrating saccular penetration of the thyrohyoid membrane, as compared with 2% of larynges excised for extralaryngeal malignancies 41 . Interestingly, the enlarged saccule is equally likely to be the saccule opposite the tumor as it is to be the ipsilateral saccule; therefore, a “ball valve” effect inadequately explains the association, and further investigation into the mechanics of saccular enlargement in laryngeal carcinoma is needed 41,42 . Accurate quantification of the association between laryngeal cysts and concurrent malignancy and the risk of malignant transformation of cysts is still required.…”

“…41 Interestingly, the enlarged saccule is equally likely to be the saccule opposite the tumor as it is to be the ipsilateral saccule; therefore, a ''ball valve'' effect inadequately explains the association, and further investigation into the mechanics of saccular enlargement in laryngeal carcinoma is needed. 41,42 Accurate quantification of the association between laryngeal cysts and concurrent malignancy and the risk of malignant transformation of cysts is still required. Further imaging of the larynx is warranted in many cases.…”

Histomorphology and Molecular Profiling of Well-Differentiated Squamous Cell Carcinoma of the Esophagus Including its Unusual Variants

“…Carcinoma cuniculatum was first described in the skin as a variant of squamous cell carcinoma peculiar to the foot. 63 Subsequently, non-cutaneous carcinoma cuniculatum cases have been reported in many different organ systems, including the esophagus, 53,[64][65][66][67][68] head, neck, [69][70][71][72][73] cervix, 74 and penis. 75 Carcinoma cuniculatum was initially considered to be a special type of VC.…”

Carcinoma Cuniculatum of the Larynx

“…The term cuniculatum refers to the complex pattern of deep invasion by keratinizing squamous epithelium lined branched rabbit burrow-like crypts and sinuses. As the CC shows, if ever, limited low-grade cytological atypia, its histological recognition may be extremely difficult, in particular on small biopsy [2][3][4].…”

“…It occurs with elective localization in the skin of the plantar surface of the foot, followed by toes and heel [2]. Rarely CC has been described in the mucosa of the upper aero-digestive tract as well [3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”