© Borgis - Nowa Medycyna 2/2017, s. 54-58
*Karolina Pasztaleniec-Iglik1, Małgorzata Kołodziejczak2, Jacek Bierca1, Iwona Sudoł-Szopińska2-4
Atypical location of leiomyoma in the left ischiorectal fossa – a case report
Nietypowa lokalizacja mięśniaka w lewym dole kulszowo-odbytniczym – opis przypadku
1Department of General Surgery, Hospital in Ostrów Mazowiecka
Head of Department: Jacek Bierca, MD, PhD
2Warsaw Proctology Centre, Saint Elizabeth’s Hospital, Mokotów Medical Centre
Head of Centre: Associate Professor Małgorzata Kołodziejczak, PhD
3Department of Radiology, Eleonora Reicher National Institute of Geriatrics, Rheumatology and Rehabilitation, Warsaw
Head of Department: Professor Iwona Sudoł-Szopińska, MD, PhD
4Department of Diagnostic Imaging, Second Faculty of Medicine, Medical University of Warsaw
Head of Department: Professor Wiesław Jakubowski, MD, PhD
Mięśniak gładkokomórkowy jest nowotworem łagodnym wywodzącym się z komórek mięśniowych gładkich. U kobiet najczęstszą lokalizacją mięśniaka jest macica. Częstą lokalizacją tych zmian jest także warstwa mięśniowa właściwa przewodu pokarmowego, w tym przede wszystkim żołądka i jelita cienkiego. Umiejscowienie mięśniaka w okolicy anorektalnej jest rzadkie. Autorzy przedstawiają przypadek pacjentki z bezobjawowym mięśniakiem gładkokomórkowym zlokalizowanym w lewym dole kulszowo-odbytniczym, który został wykryty podczas tomografii komputerowej miednicy mniejszej i potwierdzony w przezodbytniczym badaniu ultrasonograficznym. Obraz zmiany w tych badaniach nie był charakterystyczny i wymagał różnicowania z innymi patologiami, łącznie z nowotworem złośliwym. Guz został wycięty w całości z dostępu kroczowego. Przebieg pooperacyjny był niepowikłany, nie stwierdzono wznowy odległej po pół roku od zabiegu.
Wnioski. 1. Mięśniak gładkokomórkowy może lokalizować się w dole kulszowo-odbytniczym. 2. Tomografia komputerowa i ultrasonografia przezodbytnicza pozwalają na jego wykrycie, określenie wielkości, morfologii i lokalizacji, w tym stosunku do odbytnicy i kanału odbytu. 3. Obraz mięśniaka w badaniach obrazowych nie pozwala na określenie jego typu histopatologicznego, decyduje ocena patomorfologa. W różnicowaniu należy wziąć pod uwagę również nowotwory złośliwe.
Leiomyoma is a benign tumour originating from smooth muscle cells. The uterus is the most common location for leiomyoma in women. The muscle layer of the digestive tract, stomach and small intestine in particular, is also a common location for these lesions. Anorectal location is very rare. We present a case of a female patient with asymptomatic leiomyoma located in the left ischiorectal fossa, which was found in pelvic CT and confirmed by transrectal ultrasound. The presentation of the lesion was nonspecific and required differentiation against other pathologies, including malignancies. A total resection through a perineal approach was performed. The postoperative period was uneventful; no distant recurrence was observed 6 months after surgery.
Conclusions. 1. The ischiorectal fossa is a possible location for leiomyoma. 2. Computed tomography and transrectal ultrasonography allow for its detection, determination of its size, morphology and location, including its relation to the rectum and the anal canal. 3. The imaging presentation of leiomyoma does not allow to determine its histopathological type. Pathomorphological findings are decisive. Differentiation should also include malignancies.
Leiomyoma is a benign tumour originating from smooth muscle cells. The uterus is the most common location in women. However, these lesions may also develop in the muscle layer of the digestive tract, stomach and small intestine in particular. Anorectal location of leiomyoma is rare, with only single cases reported in the literature (1-5).
Classification system published by Billings et al. in 2001 distinguished two types of leiomyomas: leiomyomas of somatic soft tissue and retroperitoneal-abdominal leiomyomas) (6).
The first group of lesions is usually located in the lower or upper limbs, trunk, the axillary region, and the back. The incidence among men and women is approximately equal. No recurrences or distant metastases are observed.
The second group of leiomyomas develops in the retroperitoneal space and abdominal cavity. It mainly affects women, postmenopausal in particular. Recurrences and metastases are also rare in this group.
The clinical manifestations of anorectal leiomyoma depend on its size and anatomical location relative to the rectal wall and the anal canal. The tumour may be asymptomatic and found accidentally. Large tumours may cause rectal wall compression resulting in a sensation of ineffective tenesmus, pain and even sub-obstruction as well as symptoms of incontinence in the case of sphincteric involvement. The diagnosis is based on clinical examination, imaging techniques and histopathology.
A 62-year-old woman was admitted for a scheduled resection of a tumour located in the left ischiorectal fossa. The tumour was found accidentally, during pelvic and abdominal CT performed 2 years ago. The tumour had a diameter of 20 mm at that time. Biopsy was performed and showed connective and muscle tissue components without cytological features indicating malignancy.
The patient was treated due to Hashimoto’s disease. She also underwent a resection of right arm lipoma several years ago. The patient was in good overall condition, with no fever or pain. Thoracic and abdominal physical examination showed no abnormalities. Rectal examination detected a palpable pathological mass, about 40-50 mm in size, deforming the rectal wall, in the anal canal on the left side.
Colonoscopy showed no abnormalities. CT showed an oval focal lesion 30 x 45 mm in size, with smooth outline, located in the adipose tissue in the left ischiorectal fossa. Transrectal ultrasound (fig. 1a-c) showed a well-delineated, hypoechoic focal lesion with inhomogeneous echogenicity, adjacent to and deforming the external anal sphincter in the left periphery, located in the adipose tissue of the left buttock. About 2/3 of the length of the lesion was adjacent to the anal canal, including the distant end of the puborectal muscle. Transverse plane dimensions were 40 x 20 mm.
Fig. 1a-c. Transrectal (a, b) and transperineal ultrasound (c) shows a solid focal hypoechoic lesion with homogeneous echogenicity, adjacent to the anal sphincters throughout their length, with transverse plane dimensions of 28 x 16 mm, 40 mm in the long axis. Other than that, the anal canal unremarkable
The patient was scheduled for tumour resection. She received a prophylactic dose of first-generation cephalosporin before the procedure.
Description of the surgical procedure
The surgery was performed in a left-sided position. Guided by rectal palpation, a radial incision was performed in the left anal region to reach a nodular, well-delineated lesion about 50 mm in size, located in the left ischiorectal fossa. The tumour was dissected and removed, with the sphincter muscles moved away. The wound was controlled and hemostasis was performed. A surgical speculum was inserted and no rectal wall damage was observed. The wound was sutured in layers. The middle part of the wound was left for healing per secundam. A dressing was placed on the wound (fig. 2a-c).
Figs. 2a-c. Surgery images (a-c): tumour resection (a, b), totally resected encapsulated tumour (c)
The postoperative period was uneventful. A follow-up after one month showed a complete healing of the wound. Another follow-up after 6 months showed no signs of recurrence.
Histopathology revealed a typical leiomyoma (white, solid, encapsulated tumour) 40 cm in diameter.
Leiomyomas are mesenchymal tumours composed of cells that differentiate into smooth muscles. Macroscopically, they present as well-delineated, round or oval, most often homogeneous in cross-section, grey or grayish-white lesions occasionally containing calcifications of various sizes. Microscopically, they present as bunches of parallel smooth muscle cells, fibrous connective tissue, possibly with areas of oedema, hyalinisation and calcifications.
The uterus is the most common location of leiomyoma in women. Anorectal leiomyomas are rare. In such cases, tumours are usually located in the rectal wall. Clinical manifestations of leiomyoma are non-specific and depend on its location. Anorectal tumours can cause discomfort, constipation, impaired urination and abnormal vaginal discharge. In the presented case, the lesion was asymptomatic and was found accidentally during a CT scan.
Imaging techniques allow to identify anorectal tumours (7-11). Focal calcifications may be visualised on radiograms. In transrectal ultrasound, leiomyomas usually present as hypoechoic (fig. 1a-c), however, they may also exhibit high or mixed echogenicity, contain calcifications, fluid regions corresponding to cysts, necrosis or degeneration. The CT density of leiomyomas corresponds to soft tissue. They may contain peripheral or central calcifications and present various enhancement patterns. Pelvic MRI, in which a leiomyoma has a variable signal: low-to-moderate in T1-weighted images, low with areas of different signal in the case of regressive lesions in T2-weighted images, with variable post-contrast enhancement, is rarely performed.
Surgical excision is a treatment of choice. Obtaining material for histopathological examination is of crucial diagnostic importance. Tumours exhibiting no atypia, necrosis, no or low mitotic activity are considered mild. Total tumour resection with a margin of healthy tissue minimises the risk of recurrence. In the presented case, a complete resection of the tumour along with the capsule and a healthy tissue margin was performed, and no recurrence was observed during a follow-up after more than 6 months.
1. The ischiorectal fossa is a possible location for leiomyoma.
2. Computed tomography and transrectal ultrasonography allow for its detection, determination of its size, morphology and location, including its relation to the rectum and the anal canal.
3. The imaging presentation of leiomyoma does not allow to determine its histopathological type. Pathomorphological findings are decisive. Differentiation should also include malignancies.
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