The tumors may arise in:
(1) base of tongue or floor of mouth
(2) palate
(3) oropharynx
(4) hypopharynx
(5) nasopharynx
(6) nose
(7) tonsil
(8) pyriform sinus
(9) epiglottis
(10) larynx or trachea
Risk factors:
(1) older adult (The mean age is in the 60's but the tumor may occur in early adulthood.)
(2) chronic alcohol abuse
(3) chronic smoking
(4) possibly HPV
Many patients present with metastases to lymph nodes. Distant metastases are early and frequent.
It has biphasic histologic features:
(1) basaloid component: small, monomorphic cells
(2) squamous component
The tumors are positive on immunostaining for keratins, with a high rate of staining with AE1, 34 beta E12 and CAM 5.2. EMA is positive in most cases.
Differential diagnosis in the histologic diagnosis:
(1) adenoid cystic carcinoma
(2) small cell undifferentiated carcinoma
Imaging studies to detect distant metastases:
(1) chest CT-scan
(2) FDG-PET scan
