Rectal Leiomyosarcoma Research Articles

Challenges in Distinguishing Rectal Leiomyosarcoma from Ovarian Malignancy: A Diagnostic Conundrum

Introduction: Rectal leiomyosarcoma is a rare malignant mesenchymal tumor accounting for <0.1% of all malignant colorectal neoplasms and carries a grave prognosis. Case Presentation: A 50-year-old postmenopausal, P3L3 woman presented with complaints of abdominal pain for two months, dark-colored loose stools, 10-15 episodes per day for 2-3 months, and gradual weight loss for 4-5 months. On ultrasonography and MRI of the pelvis, a large irregular lobulated ill-defined solid lesion was seen arising from the right side of the pelvis measuring 14x8x14cm. The right ovary was not observed to be separate from the mass. There was omental thickening and peritoneal deposits with ascites. The final impression suggested a right-sided malignant ovarian mass with peritoneal dissemination (ORADS-5) with a differential leiomyosarcoma. Her tumor markers (CA- 125; CA19-9, and CEA) were raised. Given the strong dilemma between ovarian malignancy and leiomyosarcoma and the advanced stage of the disease, the patient was planned for an ultrasound-guided biopsy of the lesion. The histopathological report revealed atypical spindle cell proliferation with myoid features with the presence of multiple mitotic figures. The diagnosis of rectal leiomyosarcoma was further confirmed with immunohistochemical tests, which were positive for actin and desmin and negative for CD 117 and S100. The patient was referred to oncosurgeon for further management and was planned for surgical resection followed by chemotherapy with intravenous doxorubicin. Conclusion: Rectal leiomyosarcoma is commonly misdiagnosed as ovarian malignancy because of its exophytic growth and similar clinical features at the time of the presentation. Hence, clinicians must be aware of these differentials for the successful management of cases.

Metastatic Rectal Leiomyosarcoma Involving the Liver: A Case Report and Literature Review

Rectal leiomyosarcoma is a very rare tumor with a poor prognosis. We report the clinical case of a 45-year-old patient who presented with an externally palpable mass during defecation, accompanied by mild rectal bleeding. Colonoscopy revealed an ulcerated, budding, hemorrhagic, semi-circumferential rectal tumor. An anatomopathological examination with immunohistochemical study confirmed the diagnosis of leiomyosarcoma. The staging showed multiple secondary liver lesions. The case was discussed in a multidisciplinary meeting, and the decision was made to initiate first-line chemotherapy. However, the patient passed away before the treatment could commence.

Rectal leiomyosarcoma as the initial phenotypic manifestation of Li–Fraumeni-like syndrome: a case report and review of the literature

BackgroundLeiomyosarcoma is a rare malignant tumor of smooth muscle origin and represents 10–20% of all soft tissue sarcomas. Primary colon and rectal sarcomas constitute < 0.1% of all large bowel malignancies. In Li–Fraumeni syndrome, sarcomas are the second most frequent cancer (25%). Li–Fraumeni syndrome is a genetic disease with a familial predisposition to multiple malignant neoplasms. This syndrome has an autosomal dominant pattern of inheritance and high penetrance characterized by germline TP53 mutations. Patients with a history of cancer who do not meet all the “classic” criteria for Li–Fraumeni syndrome are considered to have Li–Fraumeni-like syndrome. To the best of our knowledge, this article is the first report of a patient with rectal leiomyosarcoma as the initial phenotypic manifestation of Li–Fraumeni-like syndrome. The authors also present a literature review.Case presentationA 67-year-old Brazilian woman underwent anterior rectosigmoidectomy and panhysterectomy secondary to rectal leiomyosarcoma. She subsequently developed carcinomatosis and died 2 years after the operation. Her family medical history consisted of a daughter who died at 32 years of age from breast cancer, a granddaughter diagnosed with adrenocortical carcinoma at 6 years of age and two siblings who died from prostate cancer. A genetic study was carried out to identify a pathogenic variant of Li–Fraumeni syndrome. In the DNA extracted from the peripheral blood leukocyte, restriction fragment length polymorphism was analyzed to search for mutations in the TP53 gene. The DNA sequencing identified the germline pathogenic variant p. R337H heterozygous in exon 10 of TP53. The patient was classified as having Li–Fraumeni-like syndrome.ConclusionIn patients with rectal leiomyosarcoma, it is advisable to investigate the family history of cancer and perform genetic studies to screen for Li–Fraumeni syndrome.

Transanal Resection of Anorectal Leiomyosarcoma

Anorectal leiomyosarcoma (AL) is a rare and aggressive malignancy. Although the optimal treatment of AL is unknown, surgical resection with negative margins is the mainstay of management. We describe the case of a 72-year-old woman with metastatic rectal leiomyosarcoma, who initially presented with blood per rectum and worsening constipation. She was found to have a 7 × 7.3 cm mass prolapsing through the anal canal into the perineum without extraluminal extension or pathologic lymph nodes on MRI, with pathology consistent with sarcomatoid carcinoma. Transanal R0 resection was performed. Pathology showed a 6 cm high grade sarcoma consistent with leiomyosarcoma and negative margins. Two years post-resection, the patient was found to have a metastatic flank lesion, for which she underwent surgery. If accessible transanally, radical resection of AL is a valuable approach to treatment. Evidence regarding the best adjuvant treatment strategy is lacking and should be evaluated on a case-by-case basis. Number of similar cases published: 27 articles published with 51 cases of anorectal sarcoma based on a review published in 2019.

Azygos continuation of the caudal vena cava in a 14-year-old dog with rectal leiomyosarcoma.

Journal of Small Animal PracticeVolume 61, Issue 9 p. 593-594 IMAGES IN SMALL ANIMAL PRACTICE Azygos continuation of the caudal vena cava in a 14-year-old dog with rectal leiomyosarcoma D. Sainato, Corresponding Author D. Sainato domenico.sainato87@gmail.com orcid.org/0000-0002-2585-4059 Eastcott Veterinary Hospital, Swindon, SN3 3FR UKCorresponding author email: domenico.sainato87@gmail.comContribution: Conceptualization, Data curation, Formal analysis, Funding acquisition, ​Investigation, Methodology, Resources, Supervision, Validation, Visualization, Writing - original draft, Writing - review & editingSearch for more papers by this authorT. Charlesworth, T. Charlesworth Eastcott Veterinary Hospital, Swindon, SN3 3FR UK Contribution: Conceptualization, Data curation, Formal analysis, Funding acquisition, ​Investigation, Methodology, Resources, Supervision, Validation, Visualization, Writing - original draft, Writing - review & editingSearch for more papers by this author D. Sainato, Corresponding Author D. Sainato domenico.sainato87@gmail.com orcid.org/0000-0002-2585-4059 Eastcott Veterinary Hospital, Swindon, SN3 3FR UKCorresponding author email: domenico.sainato87@gmail.comContribution: Conceptualization, Data curation, Formal analysis, Funding acquisition, ​Investigation, Methodology, Resources, Supervision, Validation, Visualization, Writing - original draft, Writing - review & editingSearch for more papers by this authorT. Charlesworth, T. Charlesworth Eastcott Veterinary Hospital, Swindon, SN3 3FR UK Contribution: Conceptualization, Data curation, Formal analysis, Funding acquisition, ​Investigation, Methodology, Resources, Supervision, Validation, Visualization, Writing - original draft, Writing - review & editingSearch for more papers by this author First published: 27 July 2020 https://doi.org/10.1111/jsap.13197Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume61, Issue9September 2020Pages 593-594 RelatedInformation

Systematic review of anorectal leiomyosarcoma: Current challenges and recent advances.

BACKGROUNDThe anorectal leiomyosarcoma (LMS) is an aggressive malignant neoplasm. Owing to the rarity of LMSs, an optimal treatment modality has yet to be determined.AIMTo collect all published data on anorectal LMS characteristics, explore current treatment options, and review recent cases of postradiation LMS.METHODSA literature search of the PubMed electronic database was conducted using the MeSH terms “rectal neoplasms”, “anus neoplasms” and “gastrointestinal neoplasms” combined with “leiomyosarcoma”. The search was limited to English language and human studies. All available case reports and case series of anal or rectal LMSs that were published from the beginning of January 1996 to May 2017 were included if the diagnosis of LMS had been confirmed by histopathologic examination. Data were analyzed using simple statistics (mean, median, and standard deviation). Independent sample t-test was used to compare means for continuous variables.RESULTSA total of 27 articles reporting on 51 cases of anorectal LMS were identified. Among these cases, 11.7% had undergone previous pelvic radiotherapy (developing LMS at 13-35 years afterwards). Anorectal LMS affected the rectum in 92.2% of the cases, and no sex-based predominance was observed. Surgical resection with negative margins remains the mainstay of treatment, which can be accomplished with wide local excision or radical resection. The local recurrence rate was higher among cases who received wide local excision (30%), as compared to radical resection (20%); however, the overall rate of metastasis was 51.61% regardless of the treatment approach. The use of neoadjuvant radiation lowers the risk of local recurrence compared to adjuvant radiotherapy, and facilitates R0 resection of the tumor. Cases treated with adjuvant chemotherapy showed better rates of distant recurrence and overall survival. Nonetheless, multidisciplinary team discussion is necessary to determine the optimal management plan whilst considering patient- and disease-related factors.CONCLUSIONA multidisciplinary team approach, considering the underlying patient- and disease- related factors, is necessary for optimal management of these complex tumors.

Multidisciplinary evaluation of locally advanced leiomyosarcoma in the lower rectum: a case report and literature review

Rectal leiomyosarcoma is a rare neoplasm, and no standard therapeutic strategy has been established, other than surgical resection. The prognosis of advanced leiomyosarcoma in the rectum is poor. We describe a case of a 47-year-old man with a locally advanced rectal leiomyosarcoma who presented with anal bleeding and lower abdominal pain. After discussions by a multidisciplinary team (MDT), the patient received preoperative pelvic short-course radiotherapy followed by laparoscopic-assisted abdominoperineal resection. Adjuvant chemotherapy with doxorubicin and ifosfamide was administered postoperatively. Local recurrence was detected 13 months after the resection. The patient received chemotherapy with gemcitabine and docetaxel followed by radioactive particle implantation. Thereafter, apatinib was administered to gain systemic control. The patient died 24 months after the diagnosis. This case report draws attention to treatment with multidisciplinary therapy, as discussed by MDT, for rare locally advanced rectal leiomyosarcoma.

Leiomyosarcoma Of Rectum Mimicking Primary Ovarian Tumour

Leiomyosarcoma of rectum is a very rare mesenchymal tumour with an incidence of approximately 0.1% of all colorectal malignancies. Because of its rarity, its diagnosis, treatment and pathology often present challenges to the clinicians. The characteristics of this tumour, such as its anatomical location, heterogenous solid features on imaging and non specific lower gastrointestinal tract symptoms can be confused with those of a primary ovarian tumour. Further, a synchronously growing primary ovarian tumour may add more confusion to the diagnosis. We have reported this case of rectal leiomyosarcoma with synchronously occuring primary ovarian tumour in an elderly female presenting with a large lower abdominal mass;where clinical and radiological findings are more suggestive of a primary malignant ovarian tumour with rectal metastasis. In such situation the possibility of other primary tumor of GIT specifically leiomyosarcoma should be looked for.Here Postoperative histopathological examination and immunohistochemistry gives confirmatory diagnosis. DOI:10.21276/APALM.1561

Leiomyosarcoma of the Rectum: The First Report of Effective Treatment with Endoscopic Submucosal Dissection

Background: Rectal leiomyosarcoma (LMS) is an extremely rare smooth muscle tumor accounting for <0.1% of all rectal neoplasms.1 Because of its rarity, there is no current consensus on the adequate therapeutic strategy.2 This video demonstrates an LMS of the rectum treated effectively with endoscopic submucosal dissection (ESD). Methods/Results: A 68-year-old male patient underwent a screening colonoscopy that identified a 3 cm submucosal tumor in the lower rectum, 5 cm above the anal verge. Endoscopic ultrasonography showed a hypoechoic, homogenous, well-defined mass arising from the deep mucosa layer. Tissue sample was obtained with fine-needle aspiration that showed mesenchymal myoid cells that did not stain for CD117, chromogranin, or synaptophysin. Smooth muscle actin (SMA) was focally positive. Hence, the presumed diagnosis was a submucosal leiomyoma. An ESD was effectively performed with en bloc resection and no immediate or late complications. The total length of procedure was 225 minutes. Histology showed a cellular spindle cell neoplasm having variable eosinophilic cytoplasm and mild atypical tapering or more cigar-shaped nuclei with scattered mitotic figures. The resection specimen had tumor-free margins despite an infiltrative growth pattern. Immunohistochemistry showed diffusely positive staining for SMA and desmin, while negative for S-100 protein, GFAP, and SOX10. The Ki-67 score was <2%. The findings were compatible with a low-grade LMS of the rectum. Based on the limited evidence available in the literature, a multidisciplinary team decided for an additional full-thickness resection with transanal endoscopic microsurgery (TEM). The new specimen from the TEM was tumor free. The patient is currently on 6-month follow-up, with no signs of local recurrence or metastasis. Discussion/Conclusion: ESD may be an adequate therapy for LMS of the rectum in selected cases. Further cases need to be performed using this technique and long-term follow-up is required for all patients undergoing this technique. No competing financial interests exist. Runtime of video: 6 mins 48 secs

Transanal total mesorectal excision for a large leiomyosarcoma at the lower rectum: a case report and literature review

BackgroundRectal leiomyosarcoma (LMS) is an extremely rare disease. Previously, LMS was not properly distinguishable from gastrointestinal stromal tumor (GIST) until c-kit, a characteristic marker of GIST, was discovered in 1998. No standard therapeutic strategy for gastrointestinal LMS has been established except for surgical resection because of its rarity. Rectal LMS is often accompanied by symptoms, which can enable detection at a small size. However, when a large LMS is detected at the lower rectum, it is difficult to excise due to the narrow pelvic space.Case presentationWe present the case of an 86-year-old man with a large LMS. The LMS was asymptomatic and incidentally found at the lower rectum when he visited another hospital for management of benign prostatic hypertrophy. An abdominoperineal resection of the rectum was performed with combined resection of both seminal vesicles and a part of the prostate because tumor invasion was suspected. We used the hybrid method of laparoscopic and transanal total mesorectal excision (TaTME) approaches to achieve negative surgical margins. Late-onset urethral injury occurred in the postoperative course, which was successfully treated with a urethral catheter. The patient was discharged and received no adjuvant therapy. Local recurrence did not occur, but multiple lung metastases were detected 4 months later and the patient died 12 months after the surgery.ConclusionsThis is the first report of the hybrid method of laparoscopic and TaTME approaches to remove a large LMS at the lower rectum.

Rectal leiomyosarcoma in association with ulcerative colitis: a rare condition with an unusual presentation

Rectal leiomyosarcoma in association with ulcerative colitis: a rare condition with an unusual presentation

Leiomyosarcoma of the rectum mimicking primary ovarian carcinoma: a case report

Leiomyosarcoma of the rectum is a very rare mesenchymal tumor. Because of its rarity, its diagnosis, treatment, and pathology often present challenges to the clinician. The characteristics of this tumor, such as its anatomical location, heterogeneous solid features on imaging, and nonspecific lower gastrointestinal tract symptoms, can be confused with those of primary ovarian carcinoma. Here, we report the case of a 52-year-old-woman presenting with a low abdominal mass that was later pathologically confirmed to be a rectal leiomyosarcoma. The findings of preoperative ultrasonography, pelvic magnetic resonance imaging, and abdominopelvic computed tomography were suggestive of a malignant pelvic mass, most likely a primary ovarian carcinoma. The patient underwent explorative laparotomy, and intraoperative frozen examination revealed a sarcoma originating from the gastrointestinal tract. Low anterior resection and supracervical hysterectomy with bilateral salpingo-oophorectomy were performed. The patient’s postoperative course was uneventful, and adjuvant chemotherapy is currently being administered.

Rectal Leiomyosarcoma After Pelvic Irradiation

Rectal Leiomyosarcoma After Pelvic Irradiation

Leiomyosarcoma of the rectum following pelvic irradiation: a difficult histological diagnosis

Rectal leiomyosarcomas are very rare mesenchymal tumours. This is a case report of a rectal leiomyosarcoma diagnosed initially as a leiomyoma in a patient who had undergone pelvic radiotherapy several years previously. In addition to its pathological rarity, this case is of particular interest because it reinforces the association between pelvic irradiation and rectal leiomyosarcomas and it highlights the importance of treating suspicious cases aggressively in spite of favourable preoperative radiological and histological assessment.

Rectal leiomyosarcoma, three-year follow-up

Rectal leiomyosarcomas are rare tumors originated from smooth muscle cells. Differential diagnosis includes gastrointestinal stromal tumors (GIST), leiomyomas or schwannomas, and the differentiation of these tumors is usually made through immunohistochemistry. Due to its rarity, the standard treatment has not been defined. The purpose of this study was to present the follow-up of a patient with leiomyosarcoma of medium rectum submitted to exclusive operative treatment. The tumor size was 6 cm and it had a high mitotic index. The patient remains with good urinary function and good sphincter function, and free of the disease after a three-year follow-up.

Interstitial Nephritis Secondary to Bevacizumab Treatment in Metastatic Leiomyosarcoma

To report a case of interstitial nephritis associated with the administration of bevacizumab. A 26-year-old man diagnosed with metastatic rectal leiomyosarcoma was treated with intravenous bevacizumab 5 mg/kg and received a total of 3 doses at 2 week intervals. His creatinine had increased from 1.0 mg/dL at baseline to 1.6 mg/dL after 2 doses of bevacizumab and to 4.7 mg/dL after the third dose, prompting admission. Acute renal failure was diagnosed, and hemodialysis was initiated. A renal biopsy revealed interstitial nephritis. Renal failure resolved with cessation of the drug, and the patient did not require further hemodialysis. Bevacizumab is a recombinant humanized monoclonal immunoglobulin G antibody to vascular endothelial growth factor. Bevacizumab has shown efficacy in treatment of patients with renal cell carcinoma and colorectal cancer and has been approved by the Food and Drug Administration as a first-line treatment for metastatic colorectal cancer. Our patient had no other confounding factors that might have caused renal failure. The presence of primary glomerular disease was excluded by biopsy. According to the Naranjo probability scale, bevacizumab was the probable cause of acute renal failure in this patient. Bevacizumab can cause acute renal failure by inducing interstitial nephritis. Renal function should be monitored during bevacizumab therapy.

Gastrointestinal stromal tumor: a clinicopathological study of 74 cases

To explore a simplified and reproducible approach for the diagnosis and morphologic prognostication of gastrointestinal stromal tumor (GIST). Eighty-five cases of gastrointestinal mesenchymal tumors including 74 cases of GIST, 8 esophageal smooth muscle tumor, 1 rectal leiomyosarcoma, 1 Schwannoma, and 1 malignant fibrous histiocytoma were studied by histological evaluation along with an immunohistochemistry panel including vimentin, CD117 (c-kit), CD34, SMA, desmin and S-100. Clinicopathological correlation was performed in 31 cases of GIST that had accompanied with the available follow-up data. Among 74 GISTs, 34 arose principally from the stomach, 30 from the small intestine, and 10 other cases found in the esophagus, retroperitoneum, mesenterium and omentum. The patients' age ranged from 23 to 80 years (mean 52.5 years), with 45 males and 29 females. Histologically, the tumors composed of either spindle or oval to round cells arranged in interlacing fascicles forming whorls or cellular clusters, cytoplasm generally abundant and eosinophilic. There were 48 cases of spindle cell type, 10 cases of epithelioid cell type and 16 cases of mixed cell type. All 74 cases of GIST were positive for CD117 in a cell membranous pattern, however, some variable staining patterns of CD117 had been noticed in a few cases. In addition, 54 GISTs were also positive for CD34 (72.9%), 25 cases positive for SMA, 5 cases positive for S-100 and 5 cases positive for desmin. According to the Fletcher's scheme, GISTs in this study were divided into 4 subcategories including groups of very low risk of aggressive behavior (3 cases), of low risk (15 cases), of intermediate risk (36 cases) and of high risk (20 cases) respectively. Kaplan-Meier survival analysis of 31 GIST cases whom had been followed up for 16 to 72 months showed a statistically significant difference present among the subcategories (P < 0.01). GISTs predominantly occur in the middle and old age patients, more common in male, and positive CD117 staining is considered to be the defining marker to differentiate GIST from other mesenchymal tumors of the GI tract. Positive CD34 immun-staining, plus a CD117 positivity, strengthens further a diagnosis of GIST. Subclassification of GISTs using Fletcher's scheme appears to be simple, reproducible, and correlates well with the clinical behavior of the tumor.

Evaluation of Prognosis for Malignant Rectal Gastrointestinal Stromal Tumor by Clinical Parameters and Immunohistochemical Staining

The aim of this study was to identify associated prognostic factors influencing the outcome of curative resection of rectal gastrointestinal stromal tumor. Diagnostic immunohistochemical staining with CD34, CD117, S-100, desmin, and muscle-specific actin was performed in 46 consecutive patients with previously diagnosed rectal leiomyosarcoma who underwent curative resection from 1979 to 1999. CD44, Bcl-2, P53, and Ki-67 staining were performed on tumors rediagnosed as gastrointestinal stromal tumor for the prognostic evaluation. There were 42 (91.3 percent) patients with rectal gastrointestinal stromal tumor (18 females and 24 males; mean age, 58.4 years). Twenty-nine patients underwent radical surgical resections, such as abdominoperineal resection or low anterior resection, whereas the other 13 patients underwent wide local excision, such as transrectal excision or Kraske's operation. Sixteen tumors were classified as high-grade gastrointestinal stromal tumors, and 26 as low-grade. No tumor had a positive P53 stain. Twenty-seven patients (64.3 percent) developed recurrence or metastasis postoperatively (median follow-up, 52 months). The one-year, two-year, and five-year disease-free survival rates were 90.2 percent, 76.7 percent, and 43.9 percent, respectively. Of these patients with recurrence, subsequent resections in 12 patients with local recurrence, transarterial tumor embolism or STI-571 chemotherapies in 3 patients with distant mestastases were performed. The one-year, two-year, and five-year overall survival rates were 97.4 percent, 94.3 percent, and 83.7 percent, respectively. Bcl-2 (P = 0.007) and histologic grade (P = 0.05) in disease-free survival analysis and age < 50 years (P = 0.03) and tumor size > 5 cm (P = 0.02) in overall survival analysis were independent prognostic factors. The group with wide local excision had a higher local recurrence rate than that of the radical resection group (77 percent vs. 31 percent, P = 0.006), despite smaller tumors (4.5 vs. 7.2 cm, P = 0.05). There was no difference in the incidence of distant metastasis between the two groups. Younger age (< 50 years), higher histologic tumor grade, positive Bcl-2 status, and larger tumors (> 5 cm) were factors associated with significantly poorer prognoses for rectal gastrointestinal stromal tumor. Radical resection was superior to wide local excision in the prevention of local recurrence, but not that of distant metastases.

Retrorectal Developmental Cysts in Adults: Clinical and Radiologic-Histopathologic Review, Differential Diagnosis, and Treatment

Developmental cysts are the most common retrorectal cystic lesions in adults, occurring mostly in middle-aged women. They are classified as epidermoid cysts, dermoid cysts, enteric cysts (tailgut cysts and cystic rectal duplication), and neurenteric cysts according to their origin and histopathologic features. Although developmental cysts are often asymptomatic, patients may present with symptoms resulting from local mass effect (eg, constipation, rectal fullness, lower abdominal pain, dysuria), with a palpable retrorectal mass at digital rectal examination, or with a complication. Infection with fistulization, bleeding, and malignant degeneration are the major complications of developmental cysts. A well-defined, unilocular or multilocular, thin-walled cystic lesion is the main imaging feature. Uncommonly, a sacral bone defect and calcifications are associated with developmental cysts. The differential diagnosis includes cystic sacrococcygeal teratoma, anterior sacral meningocele, anal duct or gland cyst, necrotic rectal leiomyosarcoma, extraperitoneal adenomucinosis, cystic lymphangioma, pyogenic abscess, neurogenic cyst, and necrotic sacral chordoma. Complete surgical excision is indicated to establish the diagnosis and avoid complications.

PERIANAL PAGET'S DISEASE ASSOCIATED WITH RECTAL LEIOMYOMA-A CASE REPORT-

We encountered a case of rectal leiomyosarcoma with perianal Paget's disease. A 74-year-old man visited our hospital complaining of anal pain and bloody stool. Barium enema examination showed a protruding lesion in the rectum, and endoscopic diagnosis was a submucosal tumor of the rectum. The patient underwent Miles operation for a malignant rectal tumor. Hpwevers, histological diagnosis is unexpectedly determined to be leiomyosarcoma and perianal Paget's disease. Perianal Paget's disease is often associated with a rectal or anal malignant tumor, but is rarely associated with a rectal leiomyosarcoma.