During a follow-up that ranged from 6 to 75 months (mean: 41), no patient experienced a worsening of his or her condition, indicating that repeat aspirations and regular follow-up of limited EECC prevents recurrence of signs and symptoms and progression of the disease.
EECC has been subclassified into six types: congenital, post- traumatic, iatrogenic, postobstructive, postinflammatory, and spontaneous, depending on the etiology.
Makino and Amatsu demonstrated slower migration rates in the inferior wall in patients with EECC and suggested that this could be due to hypoxia arising from a poor blood supply.
Naim et al staged EECC according to histologic and clinical findings.
Some previous reports have shown that EECC is often more extensive than what may be suggested by the clinical findings.
* stage I: the EECC is limited to the external ear canal;
* stage II: the EECC invades the tympanic membrane and middle ear;
* stage III: the EECC creates a defect of the external ear canal and involves the air cells in the mastoid bone; and
* stage IV: the EECC extends beyond the temporal bone.
These numbers, while small, indicate that EECC apparently has no predilection for either sex.
According to most studies, spontaneous EECC is typically located in the inferior quadrant.
The most common signs and symptoms of EECC reported in previous studies were otalgia and otorrhea, with the incidence ranging from 25 to 100%.