Perianal Solitary Fibrous Tumor in a Rare Anatomical Presentation: A Case Report and Literature Review

Abstract

Patient: Male, 78-year-old Final Diagnosis: Solitary fibrous tumor Symptoms: Growth Medication:— Clinical Procedure: Excision biopsy Specialty: Pathology • Surgery Objective: Rare disease Background: Solitary fibrous tumors (SFTs) account for <2% of all soft tissue tumors and are slow-growing neoplasms of mesenchymal origin, which have been reported in various locations. They are frequently observed at the pleura and a perianal location is extremely rare. They show no predisposition by sex, are mainly benign, and usually occur between the 5 th and 7 th decades of life. Case Report: We report the case of an 80-year-old man with no comorbidities except hypertension, who presented with an asymptomatic perineal mass. Magnetic resonance imaging showed a solid tumor measuring 3.5×2.5 cm identified in the perineal midline. It was very close to the anal sphincter, showing no extension to the rectum or anus. The tumor was completely excised with negative margins. The postoperative course was uneventful and he was discharged home, free of any symptoms. The pathological examination showed a benign completely excised SFT, and no further treatment was necessary. At the 6-month and 1-year follow-ups, there was no sign of recurrence. Conclusions: A comprehensive review of all the reported cases of perianal SFTs shows that the majority of these tumors present with no symptoms and have a favorable prognosis. Diagnosis is possible only after a pathological examination. The criterion standard of treatment is complete excision with negative margins. Once excised, the tumors have low rates of recurrence and metastasis. Tumors very close to the anal sphincter and with malignant potential need to be operated on with extra care to obtain clear margins without disrupting the continence mechanism.

An Unusual Solitary Fibrous Tumor of the Ischiorectal Region

“…SFTs can occur at intraperitoneal, retroperitoneal, or pelvic locations in the abdomen, which is the second most common extra-pleural site for SFTs [12][13][14]. Other rare anatomic sites that are affected by SFTs include the head and neck region, extremities, and meninges [11,[14][15][16]. However, the sites of predilection for SFTs are the pleura, peritoneum, and meninges [17].…”

“…SFTs of the pelvic area is very rare. In addition to the sigmoid, rectum (serosa) and mesorectum, they can be found in the prostate, urinary bladder, spinal sacral canal, perineal area, and ischiorectal and ischioanal fossae [14][15][16][19][20][21][22][23][24][25][26][27][28]. There have been only a few reported cases of SFTs involving the ischiorectal fossa in the literature [15,16,19,21,22,25,26,28].…”

“…SFTs in the pelvis are generally asymptomatic until they become large enough to produce mass effects on the surrounding tissues. There are no specific clinical features of pelvic SFTs [ 15 , 16 , 19 , 21 , 22 , 25 , 26 , 28 ]. They include abdominal pain [ 28 ], difficulty in urinating, urinary retention [ 27 ], numbness and weakness in lower extremities due to nerve compression, constipation, and dysuria [ 28 , 29 ].…”

“…They include abdominal pain [ 28 ], difficulty in urinating, urinary retention [ 27 ], numbness and weakness in lower extremities due to nerve compression, constipation, and dysuria [ 28 , 29 ]. A summary of some previous cases is presented in Table 1 [ 14 - 16 , 19 - 28 , 30 - 32 ].…”

Diagnostic challenges and treatment options in patients with solitary fibrous tumor: A single-center observational study

“…Depending on the size, the disease may exhibit nonspecific symptoms due to the compression of surrounding organs. However, most SFTs are painless and slow-growing ( 9 ). Extremely rare are paraneoplastic syndromes, such as Doege-Potter syndrome or Pierre-Marie-Bamberger syndrome ( 10 ).…”