True Smooth Muscle Tumors of the Small Intestine: A Clinicopathologic, Immunhistochemical, and Molecular Genetic Study of 25 Cases

Mesenchymal Tumors of the Tubular Gastrointestinal Tract (Non-GIST): The GI Pathologist's Approach

Mesenchymal neoplasms of the gastrointestinal tract are rare compared with epithelial lesions. However, over the past few decades, the increasing volume of gastrointestinal endoscopy has expedited the recognition of several novel entities with varying clinical significance. Its spectrum extends from reactive changes and benign neoplasms to highly aggressive sarcomas. At the malignant end of the spectrum, the importance of correctly diagnosing these tumors is underscored by the specific therapeutic implications available for some tumor types (eg, tyrosine kinase inhibitors for gastrointestinal stromal tumors) that allow personalized treatments. Benign lesions frequently surface among routine polypectomy specimens, sometimes offering diagnostic challenges. However, precise classification is the only way to avoid prognostic uncertainty and overtreatment, and to recognize possible syndromic associations. Hereby, we offer a pragmatic review of the topic from the gastrointestinal pathologist's perspective, who, although more accustomed to epithelial neoplasms, can use an algorithmic approach to diagnose mesenchymal entities successfully.

Leiomyosarcoma of the abdomen and retroperitoneum; a systematic review

Background

Intraabdominal and retroperitoneal leiomyosarcomas are rare cancers, which cause significant morbidity and mortality. Symptoms, treatment and follow up differs from other cancers, and proper diagnosis and treatment of intraabdominal and retroperitoneal leiomyosarcomas is of utmost importance. We performed a systematic review to collect and summarize available evidence for diagnosis and treatment for these tumours.

Methods

We performed a systematic literature search of Pubmed from the earliest entry possible, until January 2021. Our search phrase was (((((colon) OR (rectum)) OR (intestine)) OR (abdomen)) OR (retroperitoneum)) AND (leiomyosarcoma). All hits were evaluated by two of the authors.

Results

Our predefined search identified 1983 hits, we selected 218 hits and retrieved full-text copies of these. 144 studies were included in the review.

Discussion

This review summarizes the current knowledge and evidence on non-uterine abdominal and retroperitoneal leiomyosarcomas. The review has revealed a lack of high-quality evidence, and randomized clinical trials. There is a great need for more substantial and high-quality research in the area of leiomyosarcomas of the abdomen and retroperitoneum.

Systematic Review Registration

PROSPERO, identifier, CRD42023480527.

Primary duodenal dedifferentiated liposarcoma: A case report and literature review

BACKGROUND

Dedifferentiated liposarcoma (DDLPS) is an extremely rare neoplasm that exhibits various morphologies. The tumor is characterized by immunoreactivity to MDM2 and CDK4 and can be confirmed by detecting MDM2 amplification via fluorescence in situ hybridization (FISH). Herein, we report an unusual case of DDLPS arising from the duodenum.

CASE SUMMARY

A 64-year-old man presented with repeated abdominal pain and weight loss. Radiologic studies revealed a mass of the duodenum involving the pancreas. The patient was treated with pylorus-preserving pancreaticoduodenectomy. Histologically, the tumor showed a high-grade sarcoma. Immunohistochemistry demonstrated that the tumor cells were positive for MDM2 and CDK4 expression. MDM2 amplification was detected via FISH, leading to the final diagnosis of DDLPS. Following surgery, the patient was treated in the intensive care unit due to peritonitis, and died 60 d after surgery.

CONCLUSION

To the best of the authors’ knowledge, this is the first case of primary duodenal DDLPS in Korea and the third case in the English-language literature. Care must be taken not to misdiagnose DDLPS as another high-grade tumor. Liposarcoma should be in the differential diagnosis list.

Mesenchymal tumours of the gastrointestinal tract

Mesenchymal tumours represent a heterogenous group of neoplasms encopassing benign, intermediate malignancy, and malignant entities. Sarcomas account for approximately 1% of human malignancies. In consideration of their rarity as well as of intrinsic complexity, diagnostic accuracy represents a major challenge. Traditionally, mesenchymal tumours are regarded as lesions the occurrence of which is mostly limited to somatic soft tissues. However, the occurrence of soft tissue tumours at visceral sites represent a well recognized event, and the GI-tract ranks among the most frequently involved visceral location. There exist entities such as gastrointestinal stromal tumours (GIST) and malignant gastointestinal neuroectodermal tumors that exhibit exquisite tropism for the GI-tract. This review will focus also on other relevant clinico-pathologic entities in which occurrence at visceral location is not at all negligible.

Proximal Jejunum Leiomyoma unmasked as Acute Volvulus in an adult: a rare case report with management review

Leiomyoma is one of the rarest mesenchymal tumors which usually arise from different layers of the small bowel. Since small bowel malignancy is a rare condition, these lesions are often detected incidentally. Clinical presentation of this uncommonly observed tumor includes intussusception, volvulus and perforation. However, they usually grow unnoticed until their increasing size starts causing symptoms. Volvulus, commonly seen in infants and children, refers to twisting of an intestinal loop and its mesentery, leading to bowel obstruction. The most common locations for volvulus are the sigmoid colon and caecum. Here we report a case of proximal jejunum volvulus secondary to jejunal leiomyoma in an adult and discuss the varied presentation of jejunal leiomyoma, as well as diagnostic methods and treatment options

Smooth muscle tumors of the gastrointestinal tract: an analysis of prognostic features in 407 cases

Smooth muscle tumors represent the second most common mural mesenchymal neoplasm in the gastrointestinal tract, but established criteria for prognostic assessment of these tumors are lacking. A large cohort of surgically resected intramural gastrointestinal smooth muscle tumors from 31 institutions was analyzed to identify potential prognostic features. Pathologic features were assessed by expert gastrointestinal and/or soft tissue pathologists at each center. Immunohistochemical confirmation was required. A total of 407 cases from the esophagus (n = 97, 24%), stomach (n = 180, 44%), small bowel (n = 74, 18%), and colorectum (n = 56, 14%) were identified. Patients ranged in age from 19 to 92 years (mean 55 years), with a slight female predominance (57%). Mean tumor size was 5.4 cm, with the largest tumor measuring 29 cm. Disease progression following surgery, defined as local recurrence, metastasis, or disease-related death, occurred in 56 patients (14%). Colorectal tumors were most likely to progress, followed by small bowel and gastric tumors. None of the esophageal tumors in this series progressed. Receiver operator characteristic analysis identified optimal cutoffs of 9.8 cm and 3 mitoses/5 mm² for discriminating between progressive and non-progressive tumors. Histologic features strongly associated with progression by univariate analysis included moderate-to-severe atypia, high cellularity, abnormal differentiation (defined as differentiation not closely resembling that of normal smooth muscle), tumor necrosis, mucosal ulceration, lamina propria involvement, and serosal involvement (P < 0.0001 for all features). Age, sex, and margin status were not significantly associated with progression (P = 0.23, 0.82, and 0.07, respectively). A risk assessment table was created based on tumor site, size, and mitotic count, and Kaplan-Meier plots of progression-free survival for each subgroup revealed progression-based tiers. Based on our findings, it appears that nonesophageal gastrointestinal smooth muscle tumors measuring >10 cm and/or showing ≥3 mitoses/5 mm² may behave aggressively, and therefore close clinical follow-up is recommended in these cases.

Jejunal leiomyosarcoma: Report of a rare case diagnosed on cytology

Jejunal leiomyosarcomas (LMS) are extremely rare. Of all the mesenchymal tumors of the small intestine, Gastrointestinal Stromal Tumors (GIST) comprise the majority. LMS of the small intestine have been documented as isolated reports or only a very small percentage of the smooth muscle tumors of the small intestine. Furthermore, cytological evaluation and preoperative diagnosis of small intestinal LMS is not well documented, even though cytology of small intestinal GISTs has been studied. Since preoperative diagnosis is useful in differentiating benign from malignant lesions, correctly staging malignant lesions and identifying the plan of management, preoperative cytological evaluation assumes a great significance. We report a case of jejunal leiomyosarcoma diagnosed on cytology. KEY MESSAGES: Although extremely rare, small intestinal LMS should be considered in the differential diagnosis of small intestinal mesenchymal lesions. FNAC, with preparation of cell block, and subsequent IHC can help in the preoperative diagnosis and formulating a plan of management of the patients.

Recurrent fusion of the genes FN1 and ALK in gastrointestinal leiomyomas

Leiomyomas of the gastrointestinal tract are mostly found in the esophagus, stomach, and colon. Genetic information about them is very limited and no fusion genes have been described. We present herein cytogenetic and molecular genetic analyses of two gastrointestinal leiomyomas found in the esophagus and small intestine. The esophageal leiomyoma had the karyotype 45,Y,der(X)t(X;6)(p22;p21),inv(2)(p23q35),add(6)(p21),-11[cp6]/46,XY[7]. The intestinal leiomyoma karyotype was 46,X,add(X)(q2?),der(2)add(2)(p23)add(2)(q33),add(4)(p14),add(14)(q22)[10]/47,XX,+12[2]/46,XX[1]. RNA-sequencing detected FN1-ALK fusion transcripts in both tumors. RT-PCR together with Sanger sequencing verified the presence of the FN1-ALK fusion transcripts. Fluorescence in situ hybridization using an ALK breakapart probe further confirmed the rearrangement of the ALK gene. Immunohistochemical investigation of ALK in the leiomyoma of the small intestine revealed positivity with strong granular cytoplasmatic staining in the tumor cells. This is the first ever ALK fusion reported in gastrointestinal leiomyomas. Our results are of potential clinical importance because crizotinib, a selective ALK inhibitor, has demonstrated effect in patients whose tumors harbor ALK rearrangements. Thus, ALK emerges as a possible therapeutic target in patients whose tumors, including gastrointestinal leiomyomas, carry ALK fusions.

Gastrointestinal (GI) leiomyosarcoma (LMS) case series and review on diagnosis, management, and prognosis

This review of 76 gastrointestinal (GI) leiomyosarcoma (LMS) cases that include 11 cases from the American University of Beirut Medical Center represents, to our knowledge, the largest number of combined GI LMS cases reported. The age range of GI LMS is variable, and the presentation is non-specific, making pathological diagnosis essential. LMSs usually lack CD117 and CD 34 mutations and are usually positive for smooth muscle cell markers. The review highlights surgery as the mainstay of treatment with negative margins attained most of the times. Adjuvant chemotherapy is used in around 7-27 % of the cases mainly for small intestinal and colorectal LMS. The relatively small number of patients is a limitation on outcome analysis. However, LMS has a risk of recurrence reaching 39-80 % and secondary metastasis reaching 55-71 % in small intestinal and colorectal cases. In light of the high frequency of recurrence and metastasis, enrolling patients in clinical randomized trials to investigate the role of chemotherapy, radiation therapy, and targeted therapy is required for better control of this rare aggressive GI tumor.

Postirradiation Leiomyosarcoma of Rectum Presenting as a Polyp: Case Report and Review of the Literature

Radiation-induced leiomyosarcomas of the gastrointestinal tract are rare. Very few cases have been documented to date. The histological similarity to gastrointestinal stromal tumor has raised doubts if many of the cases originally reported to be leiomyosarcoma before the widespread use of CD117 were indeed gastrointestinal stromal tumors. We present a case of post-irradiation leiomyosarcoma presenting as a rectal polyp and review the literature.

Primary leiomyosarcoma of the colon

Primary leiomyosarcomas of the gastrointestinal (GI) tract are extremely rare and highly aggressive neoplasms, and only a small number of true cases have been reported since the concept of GI stromal tumors was established. Here, we report a case of a primary leiomyosarcoma of the transverse colon. A 46-year-old Japanese male with a large mass in the right upper abdomen was admitted to our hospital. Computed tomography and magnetic resonance imaging revealed long segments of wall thickening of the transverse colon with large consecutive tumors measuring 12 cm in diameter. A projecting irregular mass with marked mucosal necrosis was found on colonoscopy. Pathological examination revealed a spindle cell tumor growing circumferentially and transmurally to replace the muscularis propria in the transverse colon. The spindle cells were positive for smooth muscle actin, and negative for KIT, CD34, DOG-1, and S-100 protein. The patient has shown repeat recurrence in spite of sufficient surgical excision being promptly performed.

[Intra-abdominal soft tissue tumors. What needs to be known to reach the diagnosis with the help of immunohistochemistry, FISH and molecular biology]

Connective tissue tumors located inside the abdomen are a rare heterogeneous group of tumors, except for gastro-intestinal stromal tumors. They may be benign, malignant, or intermediate in terms of biologic potential. Pathologists have to remember the list of all the lesions possibly involved, with their immunohistochemical characteristics, and to know which molecular analyses are needed, with which expected results, and by which team they can be performed. The main tumor types are discussed with diagnostic tools and treatment consequences.

Smooth muscle tumors of soft tissue and non-uterine viscera: biology and prognosis

Smooth muscle tumors are here considered an essentially dichotomous group composed of benign leiomyomas and malignant leiomyosarcomas. Soft tissue smooth muscle tumors with both atypia and mitotic activity are generally diagnosed leiomyosarcomas acknowledging potential for metastasis. However, lesions exist that cannot be comfortably placed in either category, and in such cases the designation 'smooth muscle tumor of uncertain biologic potential' is appropriate. The use of this category is often necessary with limited sampling, such as needle core biopsies. Benign smooth muscle tumors include smooth muscle hamartoma and angioleiomyoma. A specific category of leiomyomas are estrogen-receptor positive ones in women. These are similar to uterine leiomyomas and can occur anywhere in the abdomen and abdominal wall. Leiomyosarcomas can occur at any site, although are more frequent in the retroperitoneum and proximal extremities. They are recognized by likeness to smooth muscle cells but can undergo pleomorphic evolution ('dedifferentiation'). Presence of smooth muscle actin is nearly uniform and desmin-positivity usual. This and the lack of KIT expression separate leiomyosarcoma from GIST, an important problem in abdominal soft tissues. EBV-associated smooth muscle tumors are a specific subcategory occurring in AIDS or post-transplant patients. These tumors can have incomplete smooth muscle differentiation but show nuclear EBER as a diagnostic feature. In contrast to many other soft tissue tumors, genetics of smooth muscle tumors are poorly understood and such diagnostic testing is not yet generally applicable in this histogenetic group. Leiomyosarcomas are known to be genetically complex, often showing 'chaotic' karyotypes including aneuploidy or polyploidy, and no recurrent tumor-specific translocations have been detected.

Clinicopathological features of primary leiomyosarcoma of the gastrointestinal tract following recognition of gastrointestinal stromal tumours

AIMS

We aimed to elucidate the clinicopathological and immunohistochemical features of leiomyosarcoma (LMS) of the gastrointestinal (GI) tract.

METHODS AND RESULTS

We encountered seven cases of GI-LMS in the colon (n = 4), rectum (n = 1), jejunum (n = 1) and stomach (n = 1). They ranged from 1 to 25 cm (median, 8.5 cm) in size and had high mitotic counts (median 38 per 50 high-power fields). Morphologically, the tumours were composed mainly of spindle cells with eosinophilic cytoplasm and various degrees of nuclear atypia and pleomorphism. Immunohistochemically, the tumours were positive for α-smooth muscle actin (86%), muscle-specific actin (71%), desmin (86%), calponin (71%), h-caldesmon (57%) and smoothelin (71%). All were negative for KIT, CD34, protein kinase C theta and DOG1. Local recurrence and distant metastasis occurred in one and three patients, respectively. We then reviewed 55 cases of GI-LMS from the era following the recognition of gastrointestinal stromal tumours. Among 29 of 55 cases for whom follow-up information was available, the estimated 5-year overall survival rate was 51.6%; tumour size ≥5 cm was correlated significantly with shorter overall survival time (P = 0.0016), while mitotic count (≥50 or ≥100 per 50 high-power fields) proved to be no prognostic factor.

CONCLUSIONS

GI-LMSs have distinctive clinicopathological and immunohistochemical features and exhibit aggressive biological behaviour.

Ileal leiomyosarcoma and lymph node granuloma. Relevance of a rare association

Leiomyosarcoma is rare in ileal location. We report the case of a 61 years old female patient presenting with ileal leiomyosarcoma occurring at 14 years after a uterine carcinoma treated by radiotherapy. The ileal tumor was treated by surgical resection. This tumor was peculiar by the macroscopic polypoid appearance and by expression of PDGFRA protein together with muscle differentiation proteins: smooth muscle actin, desmin and h-caldesmon. Lymph node necrotizing granuloma diagnosis on the surgical resection specimen lead to the diagnosis of tuberculosis and the patient was treated accordingly. At 3 years after the diagnosis, the patient was well, without recurrence or metastases. In conclusion, we report the case of a patient diagnosed with ileal leiomyosarcoma occurring 14 years after adjuvant radiotherapy for uterine carcinoma. Analysis of the intestinal resection specimen lead to the diagnosis of associated tuberculosis. Moreover, the leiomyosarcoma was peculiar by PDGFRA expression, feature which might be of clinical relevance since the treatment options in radioinduced tumors associated with other conditions are limited.

Primary leiomyosarcomas of the gastrointestinal tract in the post-gastrointestinal stromal tumor era

Most mesenchymal neoplasms of the gastrointestinal tract are currently classified as gastrointestinal stromal tumors (GIST). Gastrointestinal stromal tumors are diagnosed by immunopositivity for CD117, CD34, and DOG1.1, with or without molecular analyses. According to the World Health Organization classification, the diagnosis of primary leiomyosarcomas of the gastrointestinal tract is so rare that there are no significant data on demographic, clinical, or gross features of this tumor. A comprehensive literature search was performed to identify gastrointestinal leiomyosarcomas. Searches were limited to the past 12 years because definitive tools to differentiate leiomyosarcomas from GIST were introduced in the late 1990s. Cases were included only if convincing data were presented. Six cases of esophageal leiomyosarcoma and 5 cases of gastric leiomyosarcoma were confirmed. Furthermore, 26 cases of leiomyosarcoma of the small bowel, 11 cases of the colon, and 8 cases arising in the rectum were identified. Finally, 28 cases of infantile and adolescent leiomyosarcoma were reviewed. Although survival analysis is precluded by small case numbers and limited survival data availability, the trend identifies that increased size and mitotic activity portends to a worse prognosis in small bowel leiomyosarcomas. Colonic leiomyosarcomas appear to be aggressive tumors, regardless of tumor size and mitotic activity. Rectal leiomyosarcomas present as smaller tumors with favorable prognosis. Leiomyosarcomas in post-GIST era are rare tumors of the gastrointestinal tract with distinctive clinicopathologic characteristics. Owing to different treatment options, it is necessary to accurately differentiate these from GIST, using a combination of histologic appearance, presence of smooth muscle antigens, and absence of specific GIST immunomarkers.

Immunohistochemical and morphological features of a small bowel leiomyoma in a black crested macaque (Macaca nigra)

Background

Spontaneous gastrointestinal neoplasms in non-human primates are commonly seen in aged individuals. Due to genetic similarities between human and non-human primates, scientists have shown increasing interest in terms of comparative oncology studies.

Case presentation

The present study is related to a case of an intestinal leiomyoma in a black crested macaque (Macaca nigra), kept on captivity by Matecaña Zoo, Pereira City, Colombia. The animal had abdominal distension, anorexia, vomiting, diarrhea and behavioral changes. Clinical examination showed an increased volume in the upper right abdominal quadrant caused by a neoplastic mass. The patient died during the surgical procedure. Necropsy revealed several small nodules in the peritoneum with adhesion to different portions of the small and large intestines, liver, stomach and diaphragm. Tissue samples were collected, routinely processed and stained by H&E. Microscopic examination revealed a mesenchymal tumor limited to tunica muscularis, resembling normal smooth muscle cells. Neoplastic cells were positive for alpha-smooth muscle actin and vimentin, and negative for cytokeratin AE1/AE3 by immunohistochemistry. Those morphological and immunohistochemical findings allowed to diagnose the intestinal leiomyoma referred above.

Conclusion

Neoplastic diseases in primates have multifaceted causes. Their manifestations are understudied, leading to a greater difficulty in detection and measurement of the real impact provides by this disease.