Mature teratomas are the commonest benign tumors of the ovary. They account for 20–50 % of all ovarian tumors and are more prevalent in premenopausal females. In clinical practice, they are characterized by a unilateral involvement, which is often on the right side, although up to 10% cases can be bilateral [3, 4]. Pathologically, ovarian teratomas are germ cell tumors. The word was first used by Virchow in 1863 and was derived from the Greek ‘teras’, meaning ‘monster’ [1, 2, 5].
Mature ovarian teratomas are indolent and asymptomatic tumors. Their diagnosis is often incidental either during routine pelvic examination or abdomino-pelvic imaging performed for other indications. However, some patients may present with symptoms that are often secondary to tumor related complications. These include acute abdomen, abdominal lump, LUTS or sepsis. Very rare clinical features such as passage of hair in the urine (pilimiction), gross hematuria, passage of hair through the anal orifice, small bowel obstruction and fistula into the rectum are also reported in the literature [5, 6, 7].
Torsion is the commonest complication of mature ovarian teratoma occurring in 16% of the cases. Other uncommon complications include tumor rupture (1–4%), malignant transformation (1–2%), infection (1%), invasion into adjacent viscera (< 1%) and very rarely, autoimmune hemolytic anemia and paraneoplastic syndrome [5–8]. Invasion and rupture of the tumor might involve adjacent pelvic and abdominal structures most commonly the urinary bladder. There are also case reports of involvement of rectum, vagina, small intestine, sigmoid colon, anterior abdominal wall, and peritoneal cavity .
The anatomic proximity of urinary bladder to the ovaries makes it vulnerable to direct involvement by tumors of ovarian origin. The clinical presentation of this rare occurrence depends on the extent of bladder involvement and biologic nature of the tumor. According to our literature review, superficial involvement of the bladder wall often presents with irritative LUTS such as frequency and urgency. On the other hand, deeper invasion into the bladder lumen by the teratoma manifest itself with urinary tract infection (UTI), hematuria and LUTS. Many of these features are non-specific and can be easily overlooked. Pilimiction, however, is a rare but pathognomonic feature of full thickness bladder wall invasion by ovarian teratoma. At times, the hair in the bladder lumen might create an obstructive ball at the bladder outlet and manifest as acute urinary retention [1, 4, 5, 9].
Pilimiction was first reported in 1700 by Wallace. Its presence is a specific and diagnostic indicator of ovarian teratoma and fistula formation. Localized ovarian teratomas do not pose a diagnostic difficulty on their own. However, involvement of the urinary bladder is often diagnosed late unless patients present with pilimiction like the case in our patient.
In most of similar cases reported so far, the definitive diagnosis was made through the use of cystoscopy, computed tomography (CT) scan, or laparotomy [1, 5, 10]. There are also few reports on laparoscopic diagnosis and management of mature teratoma with bladder involvement .
Previous reports attributed the pathogenesis of bladder involvement to malignant transformation of the teratoma at some point in time leading to aggressive invasion of adjacent pelvic organs . However, with detailed research of the cases and pathology specimens, it was shown that benign teratomas can also cause fistula formation with nearby structures. Intermittent leakage of tumor contents can lead to chronic inflammatory process and adhesion formation resulting in fistulation. This is particularly common during tumor necrosis, torsion, and infection. Chronic pressure of the tumor on adjacent organs is also suspected as a possible mechanism for fistula formation [9, 10].
The urologist has a vital role in the management of such conditions. A joint involvement of a gynecologist and urologist is recommended. Surgical resection of the lesion and ipsilateral fallopian tube together with partial bladder resection is recommended. A malignant transformation should be ruled out with histopathological examination of the surgical specimen .