Histopathological study of the müllerian duct remnant: clarification of disease categories and terminology

We determined by histopathological studies whether there is an etiological difference in 2 distinct categories of müllerian duct remnant diseases. In addition, we clarified the nomenclature of these diseases.

We recently performed radical prostatectomy in a patient with prostate cancer associated incidentally with a so-called müllerian duct cyst in the prostatic midline. The specimen was examined by pathological and immunohistochemical testing with special attention to the relationship of the cyst and utricle. We also investigated the histology of so-called enlarged prostatic utricles or vagina masculinus extirpated from patients with severe hypospadias or intersex disorder.

The round cyst removed with the prostate seemed to arise from the verumontanum and it contained fluid with a high concentration of prostate specific antigen. Histological and immunohistochemical examination of its lining epithelium demonstrated that cyst characteristics were identical to those of the prostatic utricle. On the other hand, pouches extirpated from patients with pediatric problems were lined by squamous epithelium.

The so-called müllerian duct cyst appeared to originate from the prostatic utricle, and so should be termed a utricular cyst or cystic utricle. Conversely the so-called enlarged prostatic utricle should be termed a vagina masculinus or male vagina. The term müllerian duct remnant, which would include these 2 abnormalities, may usefully be replaced by the term utricular abnormalities.