Myofibroblastic tumours: neoplasias with divergent behaviour. Ultrastructural and flow cytometric analysis

Cancer Stem-Like Cells in a Case of an Inflammatory Myofibroblastic Tumor of the Lung

Background: Inflammatory myofibroblast tumor (IMT) is a rare tumor with obscure etiopathogenesis in which different inflammatory cells and myofibroblastic spindle cells are seen histologically. Although the majority of these neoplasms have a benign clinical course, the malignant form has also been reported. The gold standard is surgical treatment for complete removal. Our report describes a 50-year-old woman who underwent surgery for IMT of the lung. The aim is to determine whether cancer stem cells may be present in IMT of the lung.

Methods: In April 2018, the patient underwent surgery for tumor mass asportation through lateral thoracotomy. The histology of the tumor was consistent with IMT of the lung. The ALDEFLUOR assay, after tissue digestion, was used to identify and sort human lung cancer cells expressing high and low aldehyde dehydrogenase (ALDH) activity. SOX2, NANOG, OCT-4, and c-MYC positivity were additionally determined by immunohistochemistry.

Results: The specimen contained 1.10% ALDH^high cells among all viable lung cancer cells, which indicates the population of cancer stem cells is not negligible. Immunohistochemically assessed cell positivity for ALDH1A1, SOX2, NANOG, OCT-4, and c-MYC, which are considered as lung cancer stem-like cells markers.

Conclusion: For the first time, we demonstrated the presence of cancer stem cells in a case of IMT of the lung. This finding may provide a base for considering new pathological and molecular aspects of this tumor. This perspective suggests further studies to understand the possibility of developing recurrence depending on the presence of cancer stem cells.

Inflammatory myofibroblastic tumour

While initially controversial, the proposal that a subset of inflammatory pseudotumours were myofibroblastic neoplasms is now acknowledged. Inflammatory myofibroblastic tumour is a spindle cell neoplasm of intermediate biological potential that may arise in a wide range of anatomic sites but has a particular propensity for the lung and abdominal soft tissues. Depending on its location, IMT may present with a variety of clinical symptoms and it may also express a variable pathologic phenotype, leading to a broad range of clinical and pathological differentials. Recent discoveries about the molecular signatures of IMT not only provide additional tools to assist in their diagnosis, they also point to possible therapeutic interventions that may transform the management algorithms for patients with this condition.

Endobronchial Inflammatory Myofibroblastic Tumour-A Case Report

Lung malignancies are on the rise and sadly present at an advanced stage. Fiberoptic bronchoscopy is used for staging as well as in diagnosis of lung malignancies. However, not all endobronchial growth are malignant. Inflammatory Myofibroblastic Tumour (IMT) is one of the rare tumours of the lung. A controversy regarding the benign versus malignant nature of the tumour is still ongoing. The management of these tumours can be challenging because there are no established treatment protocols. Although IMT most commonly arises from lung, endobronchial presentation is very rare. We report a case of endobronchial presentation of IMT and discuss about its aetiology and treatment options.

Inflammatory myofibroblastic tumor: A rare cause of invagination in adults

Inflammatory myofibroblastic tumor (IMT) is a distinct pseudosarcomatous lesion arising in the soft tissues and interior organs of children and young adults. It is rarely seen in adults. It was first described in lungs. IMT can occur in any location in the body. However, it is seen most commonly in lungs, intestinal mesentery and liver. Non-mesenteric alimentary tract IMT's are quite rare. The presented case is an ileal IMT that caused small bowel invagination. A 38 year-old male patient presented to the emergency department with the complaint of diffuse abdominal pain, distension and no passage of gas or stools for two days. An abdominal examination revealed distension and tenderness in the abdomen with no guarding or rebound tenderness. Computerized tomography (CT) of the abdomen was ordered. CT revealed an image compatible with invagination of the right lower quadrant of the abdomen and a mass inside the lumen measuring 4x3x3cm. The mass causing invagination was detected during the surgical operation. A segmentary small bowel resection and ileoileal anastomosis was performed. The patient was discharged uneventfully on the postoperative sixth day. The diagnosis of IMT was confirmed histologically and immunochemically.

Unusual Radiologic Finding of Intracranial Inflammatory Myofibroblastic Tumor Presenting a Cyst with Mural Nodule

An intracranial cyst tumor with a mural nodule can be representative of some types of brain tumors, but is a rare presentation of intracranial inflammatory myofibroblastic tumor (IMT). Herein, we report the case of an intracranial IMT in a 48-year-old woman presenting with the extremely unusual radiologic findings of a cyst with a mural nodule.

Malignant Inflammatory Myofibroblastic Tumor of the Urinary Bladder in a 14-Year-Old Boy

Inflammatory myofibroblastic tumor (IMT) is an uncommon lesion with variable clinical behaviors from benign to mimicking malignant tumors. On rare occasions, IMT may exhibit malignant transformation, and the strategy of malignant IMT is remained undetermined. Herein, we report an extremely unusual case of IMT with malignant transformation of the urinary bladder in a 14-year-old boy characterized by local aggressive behavior and was successfully treated by combined surgery and perioperative chemotherapy.

Voluminous omental inflammatory myofibroblastic tumor in an elderly man: a case report and literature review

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm of intermediate biologic potential, with uncertain etiology. This tumor occurs primarily in the lung, but the tumor may affect any organ system. A 75-year-old male was evaluated for voluminous palpable high abdominal mass with continuous and moderately abdominal pain, associated with abdominal distension for the last two months. Abdominal computed tomography showed a large (32 × 29 × 15 cm) heterogeneously enhanced mass with well-defined margins. At surgery, the mass originated from the greater omentum was completely excised. Histologically the tumor was a mesenchymal neoplasm in smooth muscle differentiation and was characterized by spindle-cell proliferation with lymphocytes, plasma cells, and rare eosinophils. Immunohistochemically, the tumor cells were positive for vimentin and smooth muscle actin and negative for anaplastic lymphoma kinase. Complete surgical resection of IMTs remains the mainstay of treatment associated with a low rate of recurrence. Final diagnosis should be based on histopathological and immunohistochemical findings. Appropriate awareness should be exercised by surgeons to abdominal IMTs in combination with constitutional symptoms, abnormal hematologic findings, and radiological definition, to avoid misdiagnosed.

Inflammatory myofibroblastic tumor of the liver mimicking an infiltrative malignancy in computed tomography and magnetic resonance imaging with Gd-EOB

Inflammatory myofibroblastic tumors (IMT) are a benign tumor entity, which rarely develop in the liver. Surgery is the most common treatment for these lesions as it is difficult to distinguish them from malignant liver tumors and local recurrent growth may occur. IMT is a diagnostic challenge for imaging. Only a limited number of reports of single cases or small number of patients described the imaging features on computed tomography. Reports on IMT appearance on magnetic resonance imaging are scarce. We present a case of IMT of the liver with infiltration of the abdominal wall treated with surgery and describe the imaging features with the use of the hepatobiliary contrast agent, gadoxetic acid (Gd-EOB).

Inflammatory myofibroblastic tumor of maxilla showing sarcomatous change in an edentulous site with a history of tooth extraction following periodontitis: A case report with discussion

Inflammatory myofibroblastic tumor (IMT) is a rare tumor of uncertain origin with variable biological behavior ranging from reactive lesions to highly aggressive malignancy. Oral IMTs are extremely rare and only 25 cases had been reported so far. A case of IMT with sarcomatous transformation in an extraction site with a history of tooth extraction following tooth mobility of an upper left molar tooth is presented here. The tooth was extracted following a complaint of gingival swelling and mobility of tooth. Though malignant transformation in IMTs had been documented in the extra oral sites, wide search of associated literature suggests, this is the first case of oral IMT showing malignant change associated with gingiva. The case report attempts to highlight the variant possibilities of tooth mobility other than periodontitis and the importance of assessing the primary cause of such conditions.

Inflammatory myofibroblastic tumor of the colon with an unusual presentation of intestinal intussusception

Inflammatory myfibroblastic tumor (IMT), also known as inflammatory pseudotumor is unusual, benign solid tumor. This tumor is commonly reported in the lungs but can be present in extrapulmonary sites as well. We present the case of a 7-year-old girl with IMT in an unusual location. The patient was admitted with abdominal pain, and ultrasound showed a solid mass in the abdomen. She was operated and colocolic intussusception secondary to a mass was found. Histologic evaluation of mass revealed IMT.

A rare case of an inflammatory myofibroblastic tumor in a middle-aged female

Inflammatory myofibroblastic tumors (IMTs) are distinct entities with specific characteristics immunohistochemically and molecularly. They are regarded as “intermediate malignancy” tumors of unknown etiology. We report a case of a 64-years-old woman with a fever and abdominal discomfort for 3 months; a computer tomography was performed indicating gastrointestinal stromal tumor. Histologically the lesion proved to be IMT of the abdomen.

Inflammatory pseudotumor of the lateral ventricle in a pediatric patient

Inflammatory pseudotumor (IP) is a benign process that most commonly occurs in the lung and orbit. Extension into the central nervous system is extremely rare, and primary intraventricular lesions of the lateral ventricles are even more infrequent with only 2 cases reported in pediatric patients to date. Here, the authors present an unusual case of IP occurring in a 16-year-old female presenting with a 2-week history of progressive headaches and vomiting, without focal neurological deficits or radiographic evidence of hydrocephalus. The patient underwent left parietal craniotomy and complete resection of the tumor, with no signs of recurrence at 3-month follow-up. Although the rarity of intraventricular IP in pediatric patients can make its initial identification difficult, IP should be considered as a potential diagnosis in this population wherein good outcomes may be achieved following surgical resection.

Pediatric fibroblastic and myofibroblastic lesions

Fibrous lesions of infancy and childhood are a heterogeneous group of entities composed predominantly of fibroblasts and myofibroblasts, ranging from reactive lesions to neoplasms with a range of malignant potential. Although rare, their correct recognition by histopathology is important clinically as they exhibit a wide range of behaviors and may be associated with distinct underlying syndromes. Contributions from molecular diagnostics have enabled more accurate diagnosis, and have changed our concepts of some tumor types. In this review, we discuss the clinicopathologic spectrum of fibroblastic and myofibroblastic lesions of childhood and adolescence.

Inflammatory myofibroblastic tumor of the rectum in a 13-month-old girl: a case report

Inflammatory myofibroblastic tumor is a rare benign neoplasm. It is common in children and has been reported in various locations throughout the body but rarely in the rectum. A 13-month-old girl presented with a short history of a painless anal mass and no hematochezia. The mass was completely excised, and histologic examination of the initial biopsy showed fascicles of spindle cells in a mixed inflammatory background with predominance of plasma cells, typical of an inflammatory pseudotumor. The spindle cells were positive for smooth muscle actin and anaplastic lymphoma kinase staining. There is no evidence of recurrence or metastasis after a follow-up of 4.5 years.

The immunohistochemical profile of oral inflammatory myofibroblastic tumors

OBJECTIVE

The aim of this study was to demonstrate the immunohistochemical profile of oral inflammatory myofibroblastic tumors (IMTs) along with morphologic analysis.

STUDY DESIGN

Three cases diagnosed as oral IMTs were selected to compile an immunohistochemical panel constituted by calponin, caldesmon, Bcl-2, desmin, fibronectin, CD68, Ki-67, S100, anaplastic lymphoma kinase (ALK), α-smooth muscle actin, cytokeratins AE1/AE3, muscle-specific actin, CD34, and vimentin. An oral squamous cell carcinoma with a focal area of desmoplastic stroma was used as control for the stained myofibroblastic cells.

RESULTS

All oral IMTs were positive for calponin, revealing a strong and diffuse expression in the spindle-shaped cells. The lesions were also positive for vimentin (3/3), fibronectin (3/3), α-smooth muscle actin (3/3), and muscle-specific actin (1/3) and negative for h-caldesmon, Bcl-2, desmin, CD68, Ki-67, S100, ALK, cytokeratins AE1/AE3, and CD34.

CONCLUSIONS

Within the results encountered, the present panel should be of great assistance in the diagnosis of oral IMTs.

[Myofibroblastic sarcoma of the larynx : a case report and review]

BACKGROUND

Myofibroblastic sarcomas or myofibrosarcoma, are extremely rare malignant neoplasms of myofibroblasts. They are characterized by the pattern of cells and special immunohistochemical markers such as vimentin, desmin and alpha-smooth-muscle actin.

PATIENT AND METHOD

The case of a patient with a history of frequently relapsing papillomas of the larynx is reported. Chronic laryngitis with focal low-grade dysplasia of the squamous epithelium was diagnosed approximately 1 year after the first treatment of the papillomas. After approximately 2 years the pathologist diagnosed the rare myofibroblastic sarcoma of the larynx. The patient underwent laryngectomy due to the spread of the tumor with a bilateral selective neck dissection. The patient is at present still free of recurrence and metastases.

RESULTS AND CONCLUSIONS

There is a great danger of misjudging a myofibroblastic sarcoma as an inflammatory myofibroblastic tumor and consequently to delay the urgently needed treatment. Therefore, an overview of the present state of knowledge about diagnosis and treatment of myofibroblastic sarcomas will be given based on this case report.

Retroperitoneal inflammatory myofibroblastic tumor

Inflammatory myofibroblastic tumors are rare, and those located retroperitoneally are even rarer. The authors present the case of a 52-year-old male farmer with a lump in the lower abdomen of 2 months in duration that was retroperitoneal in location. It was excised, and histopathologic examination revealed an inflammatory myofibroblastic tumor. The present case is presented by virtue of its rare location.

Posterior fossa intracranial inflammatory pseudotumor: a case report and literature review

BACKGROUND

Intracranial inflammatory pseudotumors are rare. This study describes an intracranial inflammatory pseudotumor at the left cerebellopontine angle. It is the second documented posterior fossa intracranial inflammatory pseudotumor, and it was treated by surgery and radiotherapy.

CASE DESCRIPTION

A 49-year-old man presented with dizziness for 3 months and mild hoarseness for 1 month. Brain CT detected an intracranial tumor at the left cerebellopontine angle. Magnetic resonance imaging revealed a 3.6-cm heterogeneously enhancing mass. Suboccipital craniectomy with ventriculostomy was performed. The mass was well defined with a smooth surface, enclosed the low cranial nerves, and adhered to the dura matter. Pathologic examination revealed fibrous collagenous stroma with dense infiltrates of small lymphocytes and uninucleated histiocytes. Immunopositivity for T-200 and CD-68 was noted. Special staining for mycobacteria and fungus was negative. Serologic tests were positive for EBEA-Ab, EBNA-Ab, and EB-VCA-IgG. An inflammatory pseudotumor was diagnosed. Local recurrence was found 6 months later with a left oculomotor nerve palsy. Whole-brain irradiation with a total dose of 1200 cGy in 6 fractionations was done. Remission was found in follow-up neuroimages, and no recurrence was noted in 2 years' follow-up.

CONCLUSION

Based on serologic findings and a literature review, the pathogenetic mechanism of this rare intracranial tumor is believed to be chronic reactive EBV infection. We propose that radiotherapy may be the best treatment option in the case of local recurrent intracranial inflammatory pseudotumors.

Is radical surgery necessary to head and neck inflammatory myofibroblastic tumor (IMT) in children?

PURPOSE

We report a case of head and neck inflammatory myofibroblastic tumor (IMT) in an infant. Reviewing the literature, we discuss the etiology, diagnosis, treatment, and prognosis of the head and neck IMT in children.

MATERIALS AND METHODS

A 52-day-old infant was admitted with an enlarging lesion in the right head and neck region. Following total excision, the lesion recurred and progressed to terminal stage. We performed a review of the literature on head and neck IMTs in children up to the age of 18 years and assessed the treatments and related prognosis of IMT in the head and neck region.

RESULTS AND CONCLUSIONS

The children's prognosis of head and neck IMT is diverse with different treatments. Combined treatment of surgical and corticosteroid is recommended for younger children, especially infants.

Pleomorphic myofibrosarcoma of the tibia with aneuploid DNA content

Myofibrosarcomas of the tibia are exceedingly rare, with only one case reported in the literature. We describe DNA ploidy of high-grade myofibrosarcoma of the tibia in correlation with clinicomorphologic and ultrastructural features in a 16-year-old adolescent girl. Radiological studies revealed an expanding osteolytic bone lesion in the metaphysis of proximal tibia. A biopsy was consistent with malignant fibrous histiocytoma. The final diagnosis of myofibrosarcoma was supported by light microscopy and corroborated by electron microscopy and immunohistochemistry findings. The DNA content analysis showed an aneuploid tumor. She developed local recurrence at 6 months after initial treatment with no evidence of lung metastases and 16 months later is alive with persistence of disease. This is the second case reported in the literature with this location. In this case, the high grade correlated with recurrence behavior and aneuploidy DNA content but not with metastases. By ultrastructural analyses, fibronexus and intracellular collagen persisted in high-grade myofibrosarcoma.

Inflammatory myofibroblastic tumours: where are we now?

Inflammatory pseudotumour is a generic term applied to a variety of neoplastic and non-neoplastic entities that share a common histological appearance, namely a cytologically bland spindle cell proliferation with a prominent, usually chronic inflammatory infiltrate. Over the last two decades, inflammatory myofibroblastic tumour (IMT) has emerged from within the broad category of inflammatory pseudotumour, with distinctive clinical, pathological and molecular features. IMT shows a predilection for the visceral soft tissues of children and adolescents and has a tendency for local recurrence, but only a small risk of distant metastasis. Characteristic histological patterns include the fasciitis-like, compact spindle cell and hypocellular fibrous patterns, which are often seen in combination within the same tumour. Chromosomal translocations leading to activation of the ALK tyrosine kinase can be detected in approximately 50% of IMTs, particularly those arising in young patients. This review will examine the clinical, pathological, and molecular genetic features of IMT and discuss an approach to diagnosis and differential diagnosis.

Inflammatory Myofibroblastic Tumor of the Abdominal Wall Simulating Rhabdomyosarcoma: Report of a Case

We report the case of a 6-year-old boy with a progressively enlarging mass in the anterior abdominal wall. Computed tomography showed an intensely enhancing heterogeneous lesion arising from the anterior abdominal wall muscles with intraperitoneal extension. Based on the location of the tumor and the radiological findings we made a provisional diagnosis of rhabdomyosarcoma. However, the findings of fine-needle aspiration and Trucut biopsy were inconclusive for malignancy. We performed complete excision of the mass, including the involved left costal segment. Microscopically, the tumor was composed mainly of spindle-shaped cells without malignant features, and immunohistochemical analysis revealed positive staining for actin. These findings confirmed a diagnosis of an inflammatory myofibroblastic tumor (IMT). To our knowledge, this is the first case report of an extrapulmonary IMT arising from the anterior abdominal wall.

Inflammatory myofibroblastic tumors

INTRODUCTION

Inflammatory myofibroblastic tumors (IMT) while uncommon may arise within numerous organs. Historically, the literature regarding IMT has been confined to small one organ case series, with few reviews encompassing multiple anatomic sites, and little data regarding adjuvant treatment.

METHODS

A review of patients with IMT treated at two large academic medical centers over a 15-year period was undertaken. Patient demographics, pathologic diagnoses, and pertinent clinical data were obtained.

RESULTS

Forty-four cases of pathologically confirmed IMT were identified. Tumor locations included multiple anatomic sites. Therapies included complete resection, incomplete resection, observation, or chemotherapy, and/or radiation. Five patients underwent adjuvant chemotherapy and/or radiation therapy following surgery (14%) for local aggressiveness of the tumor, invasion, positive margins, or location of tumor that was not amenable to surgical resection. A second, concomitant, histologically distinct, neoplasm was identified in five cases. Of the patients who underwent treatment three local recurrences were noted (8%) and occurred in patients with partial resection without adjuvant chemo- or radiotherapy.

CONCLUSIONS

Inflammatory myofibroblastic tumors may be a locally aggressive and destructive neoplasm. Tumor recurrence is unusual following complete surgical resection or organ-preserving combined modality therapy.

Inflammatory myofibroblastic tumor with thrombocytosis and a unique chromosomal translocation With ALK rearrangement

We describe a case of inflammatory myofibroblastic tumor with an unusual constellation of clinical, pathologic, and genetic findings. A 7-year-old girl had an 11-cm abdominopelvic mass accompanied by thrombocytosis, anemia, elevated erythrocyte sedimentation rate, and elevated C-reactive protein. The inflammatory myofibroblastic tumor displayed unusual histologic features of zonal coagulative necrosis, high cellularity with a herringbone pattern, and tumor-associated osteoclast-like giant cells. The complex tumor karyotype included a translocation t(1;2)(q21; p23). Following resection, the laboratory abnormalities resolved. The patient is well and free of recurrence at 3 years following resection. This case raises interesting questions about clinical, pathologic, prognostic, and molecular genetic interrelationships in inflammatory myofibroblastic tumor.

Hemorrhagic intracranial inflammatory pseudotumor originating from the trigeminal nerve: a case report

We report here on a case of intracranial inflammatory pseudotumor arising from the trigeminal nerve. A 52-year-old man presented with sudden onset severe headache. He had had facial numbness several months earlier and no signs indicating infection. On the computerized tomography scan, intracranial hemorrhage was detected at the cerebellopontine angle. Magnetic resonance imaging demonstrated a 2.7-cm-sized, homogenously enhancing mass. A provisional diagnosis of trigeminal schwannoma was made, and suboccipital craniotomy was then performed. The mass was encapsulated and had multiple capsular veins. There was a evidence of intratumoral bleeding. It originated from the trigeminal root and was adhered to the 4th cranial nerve. Pathologic examination showed fibrovascular tissue with dense infiltrates of plasma cells and lymphocytes, some histiocytes, and occasional neutrophils and eosinophils. It showed immunopositivity for leukocyte common antigen (LCA) and immunonegativity for S-100 and lysozyme. It was also immunopositive for EBV antigen. Intracranial inflammatory pseudotumors mostly arise from dural/meningeal structures in the intracranial location. This case is the first to describe an intracranial inflammatory pseudotumor originating from a cranial nerve. The pathologic examination supported the postinfection hypothesis out of several possible pathologic mechanisms.

Oral inflammatory myofibroblastic tumor demonstrating ALK, p53, MDM2, CDK4, pRb, and Ki-67 immunoreactivity in an elderly patient

Inflammatory myofibroblastic tumor (IMT) is a controversial lesion composed of myofibroblasts, accompanied by varying numbers of inflammatory cells. Various pathogenetic factors have been proposed (ie, reactive, infectious, autoimmune, and neoplastic) but the etiology of most IMTs remains unknown. Here we review the literature of oral IMTs, detailing the demographic profile of these rare lesions. Moreover, we present an unusual case of IMT arising from the mandibular alveolar mucosa of an 82-year-old female. Microscopic examination revealed plump spindle cells set in a myxoid vascular stroma admixed with inflammatory cells. Numerous large ganglion cell-like cells were seen, some exhibiting emperipolesis of neutrophils. Ultrastructurally, prominent myofibroblasts with abundant rough endoplasmic reticulum were noted. Tumor cells were immunoreactive for vimentin, smooth muscle actin, and KP1 (CD68), and negative for desmin, S-100, and EBV-LMP. The lesion was excised without margins and the patient has manifested no evidence of disease at an 18-month recall. In an attempt to further delineate the potential neoplastic nature of this lesion, we assessed the immunohistochemical expression of various markers that have been linked to neoplastic transformation. The recorded positivity for ALK, p53, MDM2, CDK4, pRb, and Ki-67, despite the absence of bcl-2 reactivity, strongly favors the neoplastic origin of the studied tumor.

Inflammatory myofibroblastic tumor of the uterus: a clinicopathologic study of 6 cases emphasizing distinction from aggressive mesenchymal tumors

Inflammatory myofibroblastic tumor (IMT) is an indolent spindle cell proliferation that can histologically resemble various malignant mesenchymal neoplasms; however, it generally behaves as a benign or locally recurrent tumor. Most IMTs involve the lung, mesentery, omentum, or retroperitoneum. We report the clinical and pathologic features of six IMTs of the uterus, one of which was included in a previous report, and emphasize the histologic and immunohistochemical features that distinguish IMTs from uterine spindle cell neoplasms that require aggressive treatment. Recently, translocations of the anaplastic lymphoma kinase (ALK) gene and immunohistochemical expression of ALK have been reported in IMTs of various anatomic sites. We compared ALK expression in uterine IMTs with that in uterine mesenchymal neoplasms with which it may be confused. Patients with IMT were between 6 and 46 years of age. None had a history of abdominal surgery; three were multiparous. The IMTs ranged from 1 to 12 cm in maximum dimension. Three grew as polypoid masses that arose in the lower uterine segment, and two of these prolapsed through the cervical os. The three other tumors grew as bulky myometrial masses with focally irregular borders and infiltrated the endometrium, parametrium, or cervical stroma. There were three main microscopic patterns: a hypocellular pattern, a fascicular pattern, and a hyalinized pattern. A lymphoplasmacytic infiltrate was present in all of the tumors, and most had a myxoid background. Mitotic activity ranged from 0 to 2 mitotic figures per 10 high power fields (HPF) except in one tumor that focally had up to 8 mitotic figures per 10 HPF. No nuclear atypia or necrosis was present. Immunohistochemical expression of ALK was present in a cytoplasmic pattern in all IMTs tested. No ALK expression was identified in uterine leiomyoma (n = 7), leiomyosarcoma (n = 6), carcinosarcoma (n = 4), endometrial stromal sarcoma (n = 4), or normal uterine tissues. Follow-up ranging from 1.5 years to 5 years in 4 patients with uterine IMTs revealed no recurrence or metastasis. IMTs should be differentiated from aggressive uterine mesenchymal tumors because they can be treated conservatively and have a more favorable prognosis. ALK expression appears to be of diagnostic value in conjunction with other immunohistochemical stains.

Retroperitoneal inflammatory myofibroblastic tumor

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a neoplasm of unknown etiology occurring at various sites. By definition, it is composed of spindle cells (myofibroblasts) with variable inflammatory component, hence the name is IMT.

CASE PRESENTATION

The present case is of a 46 years old woman presented with a history of flank pain, abdominal mass and intermittent hematuria for last 6 months. The initial diagnosis was kept as renal cell carcinoma. Finally, it turned out to be a case of retroperitoneal IMT. The patient was managed by complete surgical resection of the tumor.

CONCLUSION

IMT is a rare neoplasm of uncertain biological potential. Complete surgical resection remains the mainstay of the treatment.

Inflammatory myofibroblastic tumor of the central nervous system: clinicopathologic analysis of 10 cases

To verify the pathologic features, anaplastic lymphoma kinase (ALK) expression and biologic behavior of inflammatory myofibroblastic tumors (IMTs) of the central nervous system (CNS), we analyzed 10 cases of IMTs-CNS (8 cranial, 1 spinal, and 1 orbital). Our series of IMTs of the CNS showed a male predominance (male:female = 6:4) and a wide age range (10-60 years; mean age, 46.7 years). Lesion location also varied, but they were basically dura-based. Radiologically, they showed two patterns: isolated mass forming (n = 6) and an en plaque-like pattern (n = 4). Histopathologically, plasma cell granuloma (PCG)-like (n = 5) or fibrohistiocytic (FHC) variant (n = 5) was present. No correlation was found between the radiologic and histopathologic patterns. Spindle-shaped mesenchymal cells of IMTs expressed smooth muscle actin (SMA) in all cases. ALK expression was not found in our IMTs of the CNS. Late recurrence was found in 2 cases in different sites (20%). Pathologically, IMT-CNS could be subclassified into PCG-like and FHC. Immunostaining for SMA was found to helpfully discriminate myofibroblastic cells and to make a differential diagnosis. Although our cases did not show ALK immunoreactivity, some IMTs-CNS can recur, which suggests the neoplastic potential of these tumors. The rearrangement of the ALK gene in IMTs-CNS should be verified by an examination of more cases.

Abdominal inflammatory masses mimicking neoplasia in children-experience of two centers

Despite progress in modern imaging, some inflammatory masses are difficult to distinguish clinically from neoplastic processes. In such cases the pathology report has a great distinctive value, but even then the final diagnosis may be difficult to reach. Eight patients with abdominal tumors of inflammatory origin were treated in two institutions, the Department of Pediatric Surgery of the Medical University of Gdansk, Poland, and Helios Center of Pediatric Surgery in Berlin, Germany, during the last 10 years. Four tumors were located in the pelvis, two in the liver, and two in the colonic mesentery. Five of them were inflammatory pseudotumors (two subclassified as inflammatory fibrosarcoma), one had nonspecific inflammatory changes, one was diagnosed as idiopathic retroperitoneal fibrosis, and one was diagnosed as bacillary angiomatosis. All patients underwent surgical tumor biopsy, excisional in four and incisional in four. All but two children underwent macroscopically complete tumor excision (four primarily, two secondarily). In one case the tumor resolved with antibiotherapy. Surgery in retroperitoneal masses was often extensive and associated with significant complications because of invasive tumor growth. In conclusion, intraabdominal inflammatory lesions may closely mimic neoplasia in children. Clinical doubts result in repeated biopsies, and for this reason excisional biopsy should be preferred. In some cases, when excisional biopsy is not feasible due to invasive growth of the tumor, delayed complete mass excision should follow, despite occasional significant morbidity. The etiology and exact nature of inflammatory pseudotumors are still obscure, and it is unknown whether they represent inflammatory lesions or true neoplasia.

Low-grade sarcomas with CD34-positive fibroblasts and low-grade myofibroblastic sarcomas

A subset of low-grade fibrosarcomas is composed of CD34-positive spindle cells. These include dermatofibrosarcoma, its morphologic variants, and its associated fibrosarcoma, solitary fibrous tumor, hemangiopericytoma and their malignant counterparts, and some cases of myxoinflammatory fibroblastic sarcoma. Dermatofibrosarcoma and related lesions are characterized by a t(17;22)(q22;q13) rearrangement resulting in fusion of the genes COL1A (17q21-22) and PDGFB1 (22q13). Solitary fibrous tumor displays varying cellularity and fibrosis and a peripheral hemangiopericytomatous pattern; most tumors formerly called hemangiopericytoma are now subsumed into the category of solitary fibrous tumor, although a few strictly defined examples are recognized; however, these are probably not composed of pericytes. Myofibroblastic malignancies are best identified by electron microscopy, with which varying degrees of differentiation, including the presence of fibronexus junctions, can be identified. Low-grade sarcomas showing myofibroblastic differentiation include myofibrosarcomas and inflammatory myofibroblastic tumors. Myofibrosarcomas are spindle cell neoplasms that occur in children or adults in the head and neck, trunk, and extremities as infiltrative neoplasms and that display a fascicular or fasciitis-like pattern with focal nuclear atypia and variable expression of myoid antigens. These sarcomas are prone to recurrence and a small number metastasize. Inflammatory myofibroblastic tumor (synonymous with inflammatory fibrosarcoma) is a neoplasm arising predominantly in childhood, and frequently in intraabdominal locations. It has spindle cells in fascicular, fasciitis-like and sclerosing patterns, with heavy chronic inflammation including abundant plasma cells. Many IMT have clonal chromosomal abnormalities involving 2p22-24, and fusion of the ALK gene with tropomyosin 3 (TPM3-ALK) or tropomyosin 4 (TPM4-ALK) is found in a subset.

Synchronous gastrointestinal and musculoskeletal manifestations of different subtypes of inflammatory myofibroblastic tumor: CT, MRI and pathological features

We describe a case of an unusual multicentric appearance of an inflammatory myofibroblastic tumor, consisting of multiple gastrointestinal masses with different growth patterns and simultaneous, distant, musculoskeletal manifestations. CT and MR imaging features demonstrated a different degree of lesion enhancement, which proved histologically to be related to an alternation of predominantly spindle cell areas with a myxoid-vascular IMT subtype. A clear separation of the imaging characteristics of this tumor's subtypes by correlation with the pathology was not possible because of the mixed histologic character of the tumor in all its locations. However, MRI signal in the T2-weighted sequence was lower in the spindle cell variant localized predominantly in the musculoskeletal system, while the gastrointestinal predominantly myxoid-vascular counterparts showed slightly higher signal in the T2-weighted sequence.

Myofibroblastic malignancies

Malignant tumors composed of myofibroblasts are increasingly being recognized, but their existence remains controversial. Currently accepted examples within this category represent spindle cell or pleomorphic neoplasms of the soft tissues with a spectrum of histological grades. Low- and intermediate-grade myofibrosarcomas are fascicular spindle cell neoplasms resembling fibrosarcoma or leiomyosarcoma. They infiltrate deep soft tissue with disproportionate involvement of head and neck sites and can recur locally but infrequently metastasize. They variably express myoid immunohistochemical markers, and their differential diagnosis includes benign myofibroblastic proliferations such as fasciitis and fibromatosis as well as other types of spindle cell sarcoma. High-grade (pleomorphic) myofibrosarcomas are an ultrastructurally defined subset of malignant fibrous histiocytoma, which they resemble in morphology and behavior. Inflammatory myofibroblastic tumor and infantile fibrosarcoma are neoplasms that have myofibroblastic features and have been included in this category, but they have distinctive genetic findings. This article reviews the concept of myofibrosarcoma and describes its variants.

Myofibrosarcoma

Myofibrosarcomas are malignant tumours of myofibroblasts, which have been recognised for many years, but have become clearly defined only recently. They are low- or high-grade sarcomas that arise in soft tissue or bone in adults or children. Low-grade myofibrosarcomas are infiltrative tumours, usually in deep soft tissue, with a predilection for the head and neck region, which display a range of microscopic appearances from fasciitis-like to fibrosarcoma-like; all cases at least focally display nuclear pleomorphism. They express smooth-muscle actin and calponin, and some express desmin, but most lack h-caldesmon. Low-grade myofibrosarcomas can recur but rarely metastasise. Their differential diagnosis is from benign myofibroblastic proliferations, such as fasciitis and fibromatosis, as well as from fibrosarcoma and leiomyosarcoma. Pleomorphic myofibrosarcomas are high-grade pleomorphic sarcomas (malignant fibrous histiocytoma), which show ultrastructural evidence of myofibroblastic differentiation. They closely resemble malignant fibrous histiocytoma clinically and morphologically, but are more frequently actin positive. This article describes the low- and high-grade variants of myofibrosarcoma and other malignant tumours with myofibroblastic differentiation.

Follicular dendritic reticulum cell tumor mimicking inflammatory pseudotumor of the spleen

In the course of a routine clinical check up of the 54 year old male a splenic well circumscribed tumor like mass of 12 cm in diameter was discovered. Splenectomy with removal of splenic hilar lymph nodes and liver wedge biopsy were performed. Four years later the patient is symptom free. In the removed spleen the tumor like lesion showed a pattern consistent with the diagnosis of inflammatory pseudotumor. However, besides lymphocytes, plasma cells, macrophages, eosinophils and myofibroblasts a high number of slightly polymorphic, frequently binucleated cells positive for CD21 and CD23 were seen. These cells which were scattered or formed smaller or larger groups and fascicles were considered to represent follicular dendritic reticulum cells (FDRCs) and the lesion a FDRC tumor. Flow cytometric DNA ploidy analysis showed a hyperdiploid cell population inside the tumor like lesion. Besides FDRC tumors of high and of intermediate malignancy the present case may represent a low grade type of moderate proliferation activity. The FDRCs of the lesion and a few smaller spindle cells were EBER positive indicative of the presence of EBV. No EBER positive cells were seen in the uninvolved spleen.

Oligoclonal T-cell populations in an inflammatory pseudotumor of the pancreas possibly related to autoimmune pancreatitis: an immunohistochemical and molecular analysis

Inflammatory pseudotumors (IPT), also known as inflammatory myofibroblastic tumors (IMT), are benign inflammatory processes that may have an infectious etiology and are very rare in the pancreatico-biliary region. Recent studies suggest a biological distinction between IPT and IMT, the latter being a true neoplastic process. We describe a case of pancreatic IPT, originally diagnosed as malignancy, which presumably recurred 4 months after the operation. Histologically, the tumor consisted of a smooth muscle actin and CD68-positive spindle cell population and a more abundant mononuclear inflammatory cell population, primarily composed of macrophages and T-lymphocytes. Inflammatory cells were the source of connective tissue growth factor and transforming growth factor-beta1 and tended to accumulate around nerves and blood vessels, as well as around residual pancreatic parenchymal elements, where an intense angiogenetic response was detected. Comparative genomic hybridization analysis of the tumor showed no chromosomal imbalances. Polymerase chain reaction-based analysis of T-cell receptor gamma gene rearrangement revealed an oligoclonal pattern. These findings suggest that the pathogenesis of aggressive cases of IPT could be related to the development of an intense and self-maintaining immune response, with the emergence of clonal populations of T-lymphocytes. The relation of the pancreatic IPT to autoimmune pancreatitis is emphasized.

Myofibroblastoma of the larynx: a study of two cases

BACKGROUND

We describe, for the first time, the occurrence of two pure examples of spindle cell neoplasm with fibrous and smooth muscle differentiation in the larynx.

MATERIALS AND METHOD

Tissue sections from both tumors stained with hematoxylin and eosin were reviewed. Immunophenotypic analysis using keratin, S-100 protein, SMA, and h-Caldesmon markers was performed.

RESULTS

Tumors were seen as raised submucosal nodules in the glottic region of two elderly male patients. Histopathologically, the lesions were unencapsulated and composed of spindle cells that manifested variable cellular anaplasia and expressed SMA and were negative for keratin, S-100, and h-Caldesmon.

CONCLUSIONS

We document histologically low-grade malignant myofibroblastic tumors of the larynx. Complete excision is advised.

Inflammatory pseudotumors of the central nervous system: report of 3 cases and a literature review

Inflammatory pseudotumors (IPs), mostly benign lesions characterized by fibrotic ground tissue and polyclonal mononuclear infiltrate, may affect all organ systems. IPs originating in the central nervous system (IP-CNS) are very rare, and their distinct histopathologic features are poorly characterized. Three otherwise healthy patients (age 8, 15, and 17 years) presented with focal neurologic symptoms (seizures, n = 2; headaches, n = 1), corresponding to a left temporal, left occipital, and left frontal IP, respectively, extending from meningeal structures into brain tissue. After resection, no recurrence was observed in patient 1 during 5 years of follow-up, whereas patient 2 developed a rapidly progressive local recurrence and a second intracerebral lesion despite antiviral, immunosuppressive, antibiotic, and radiation therapy. In patient 3, who also showed local recurrences, sequential histopathologic investigations revealed transformation to a semimalignant fibrohistiocytic tumor. In this patient, anaplastic lymphoma kinase (ALK) expression was also positive, whereas it was negative in patient 1. A detailed literature analysis confirmed that most IP-CNS arise from dural/meningeal structures (n = 34). Intraparenchymatous (n = 7), mixed intraparenchymatous/meningeal (n = 4), and intraventricular lesions (n = 7) or IP extending per continuitatem from intracerebral to extracerebral sites (n = 5) were rare. The recurrence rate was 40% within 2 years in general. It was increased after incomplete resection and in female patients (multivariate Cox regression model, P < 0.02). Although rare, IP-CNS are important differential diagnoses among tumor-like intracranial lesions. Their potential risk of malignant transformation and high risk of recurrence necessitate close follow-up, especially when resection is incomplete. Prospective multicenter trials are needed to optimize classification and treatment of this rare inflammatory lesion.

Successful treatment of inflammatory myofibroblastic tumor with malignant transformation by surgical resection and chemotherapy

Inflammatory myofibroblastic tumor (IMT) is a tumor composed of myofibroblasts and a mixed inflammatory infiltrate that rarely undergoes malignant transformation. The authors present the case of a 7-year-old boy with an abdominal mass diagnosed as IMT with malignant transformation. The tumor recurred twice after attempts at resection and was initially treated with vincristine and etoposide. After a third recurrence and incomplete resection, he was treated with cisplatin, Adriamycin, and methotrexate. He is disease-free after 2 years, representing successful combined surgery and chemotherapy in the treatment of malignant IMT. The use of chemotherapy for aggressive myofibroblastic tumors is reviewed.

Benign spindle cell tumors of the mammary stroma: diagnostic criteria, classification, and histogenesis

Purely benign mesenchymal spindle cell neoplasms of the breast are currently labeled under various terms in the literature (benign spindle cell tumor, fibroma, spindle cell lipoma, myofibroblastoma, solitary fibrous tumor, myogenic stromal tumor). The lack of strict diagnostic criteria to clearly indicate such mesenchymal neoplasms is the main reason which generated the risk of terming the same lesion under different names or, conversely, of collecting different types under the same term. Although such neoplasms exhibit morphological and immunophenotypical heterogeneity, they actually represent variations of the same tumor entity, likely arising from the uncommitted vimentin+/CD34+ fibroblasts of the mammary stroma, capable of multidirectional mesenchymal differentiation. To cover the entire spectrum of such lesions, the term "benign spindle cell tumors (BSCTs) of the mammary stroma" is advocated. BSCTs can be subtyped into four main groups by light microscopy (LM) and immunocytochemistry (ICC): fibroblastic, myofibroblastic, fibrohistiocytic, and mixed forms. A simple and practical approach to a nosologically correct diagnosis and a list of differential diagnoses are presented. The awareness of the diversity of morphological and immunophenotypical features of BSCTs of the mammary stroma, including uncommon variants, is helpful to avoid confusion with other monomorphic bland-looking benign and malignant spindle cell tumors and tumor-like lesions of the breast.

ALK1 and p80 expression and chromosomal rearrangements involving 2p23 in inflammatory myofibroblastic tumor

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is an uncommon tumor of extrapulmonary and pulmonary tissues with an unpredictable clinical course, occasional recurrences, and rare malignant transformation. Clonal abnormalities with rearrangements of chromosome of 2p23 and the ALK gene have been reported in a few cases. The purpose of this study is to investigate whether these are consistent abnormalities among IMTs or represent a distinct subset.

DESIGN

Formalin-fixed, paraffin-embedded archival tissue sections from 47 IMTs in 40 patients were immunostained with monoclonal antibodies against ALK and p80. Fluorescence in situ hybridization for ALK rearrangements was done on 22 IMTs from 19 patients. Findings were correlated with clinical features and outcome.

RESULTS

ALK positivity was observed in 17 of 47 IMTs (36%) and p80 positivity in 16 of 47 IMTs (34%). Fluorescence in situ hybridization showed ALK rearrangements in nine cases (47%), aneuploidy in three cases (16%), and no rearrangement in seven cases (37%). IMTs with ALK abnormalities by immunohistochemistry and/or fluorescence in situ hybridization originated in the abdomen/pelvis/retroperitoneum, chest, and extremities. The mean age was 6.6 years, with a male/female ratio of 1.3. 64% of patients had no evidence of disease at last follow-up, 45% had one or more recurrences, and 18% displayed histologic evidence of malignant transformation. The IMTs without ALK abnormalities occurred in older children, were more frequent in females, and had fewer recurrences. However, in this group of 40 patients, the differences between the groups with and without ALK abnormalities did not have statistical significance. Aneuploidy without ALK abnormalities was associated with malignant transformation in three of five cases.

CONCLUSIONS

Abnormalities of ALK and p80 and evidence of chromosomal rearrangements of 2p23 occur in a significant proportion of IMTs. These changes are most frequent in abdominal and pulmonary IMTs in the first decade of life and are associated with a higher frequency of recurrence. These findings confirm the neoplastic nature of a subset IMT with ALK abnormalities and suggest that aneuploid IMT is a subset with more aggressive clinical behavior.