A rare anal mass: anal leiomyoma presented as perianal fistula

Abstract

Leiomyoma of the anal canal originating from the internal anal sphincter is an extremely rare clinical entity. Generally, it does not produce any clinical signs unless it is large enough to cause obstruction, discomfort, bleeding or pain. The diagnosis is often made incidentally during rectal examination due to other perianal disease or check-up. Herein we report a case of internal anal sphincter leiomyoma diagnosed unexpectedly during rectal examination in a patient with perianal fistula, and treated successfully with surgical excision. We present a review of the literature, the diagnostic strategies, differential diagnosis, prognosis and treatment modalities of this lesion.

Imaging Diagnosis of Perianal Leiomyoma: A Case Report

“…Among the anorectal leiomyomas, those related to the anal canal are even more uncommon. There are seven reported cases of perianal leiomyomas (Table 1) that have been confirmed by im- munohistochemical staining [1][2][3][4][5][6][7]. Before the development of immunohistochemical staining, characterization of leiomyomas was questionable.…”

“…In the digestive tract, the anorectal location is uncommon and is usually diagnosed late due to intraluminal growth in over 50% of the cases [2]. Reports of perianal leiomyomas are sparse in the literature [1][2][3][4][5][6][7]. Our aims of this case report are to present a perianal leiomyoma as a rare tumor in the gastrointestinal tract and to report the tumor on imaging diagnosis using pelvic floor ultrasound and magnetic resonance imaging (MRI).…”

Rare case of an anorectal leiomyoma

“…In the previous classification, it belonged to the so-called gastro-intestinal stromal tumor (GIST). Nowadays, the GIST is considered a soft tissue tumor, as well as the leiomyoma, but it has its own identity based on specific immunohistochemical pattern, while many tumors previously defined as leiomyoma are now classified as GIST and even have a different type of treatment [5,6]. The leiomyoma have exhibited positivity for smooth muscle actin and negativity for CD117 and CD34 (c-Kit).…”

“…On the other hand, extraluminal leiomyomas generally grow from the colonic wall inside the abdomen and they often resemble a GIST [12]. Sometimes the tumors grow in both directions, forming an "hour glass, " which could be said for this case according to the MRI [5,6].…”

“…They may include pain, rectorrhagia, tenesmus or they can be confirmed by a biopsy and the treatment depends on their alteration, which is confirmed by medical examination. Biopsy is often non-informative because it does not involve the entire tumor, including the full evolution of histological characteristics [3,6]. The radiological imaging, such as MRI or 360° tridimensional transrectal ultrasound, are useful to identify and localize the mass, to provide information on its relationship with the adjacent structures such as the anal sphincter or uro-gynecological structures and to indicate the operative strategy [5].…”