Nonsyndromic Congenital Absence of the Pectoralis Muscles.

The congenital absence of the pectoralis muscle is usually a manifestation of Poland syndrome. However, a nonsyndromic congenital absence of this muscle is rare, and such absences are usually partial and unilateral. A complete or bilateral absence is even rarer. Two young men presented to our outpatient clinic with incidentally noted unilateral flat chest walls. By chest computed tomography, they were diagnosed with a congenital unilateral absence of the pectoralis muscles. They did not show any functional disability of the arms. As the congenital absence of the pectoralis muscles is often associated with leukemia and genitourinary anomalies, it is advised that hematological testing and renal ultrasonography be performed, even in nonsyndromic cases.