Immunohistochemical analysis of anaplastic lymphoma kinase expression in deep soft tissue calcifying fibrous pseudotumor: evidence of a late sclerosing stage of inflammatory myofibroblastic tumor?

Mesenchymal tumours of the pleura: review and update

Primary mesenchymal tumours of the pleura are uncommon and can be diagnostically challenging due to their overlapping histopathologic and immunophenotypic features. Herein we discuss selected mesenchymal tumours of the pleura, including solitary fibrous tumour, calcifying fibrous tumour, desmoid fibromatosis, synovial sarcoma, schwannoma, malignant peripheral nerve sheath tumour, inflammatory myofibroblastic tumour, follicular dendritic cell sarcoma, epithelioid hemangioendothelioma, and desmoplastic small round cell tumour. We review their clinicopathologic characteristics, along with an update on the relevant immunohistochemical and molecular features.

Non-cutaneous syncytial myoepitheliomas are identical to cutaneous counterparts: a clinicopathologic study of 24 tumors occurring at diverse locations

AIMS

Cutaneous syncytial myoepithelioma (CSM) is a rare myoepithelioma variant of skin, characterized by intradermal syncytial growth of spindle cells with a distinct immunophenotype of EMA and S100 positivity and infrequent keratin expression. While CSM was first described as a cutaneous tumor, singular non-cutaneous cases have since been reported in bone. We aimed to investigate the clinicopathological features of this variant across all anatomic sites through a large multi-institutional study.

METHODS AND RESULTS

We complied a total of 24 myoepitheliomas with syncytial growth from our files. The tumors occurred in 12 male and 12 female patients (M:F = 1:1), with a median age of 31 years (range, 9-69 years). While the majority of tumors (75%, n = 18) occurred in skin, a significant subset (25%, n = 6) arose in non-cutaneous sites, including bone (n = 3), bronchus/trachea (n = 2), and interosseous membrane of tibia/fibula (n = 1). Tumor size ranged from 0.4 to 5.9 cm. Clinical follow-up (7 patients; range 14-202 months; median 56.5 months) showed a single local recurrence 8 years after incomplete skin excision but no metastases; all patients were alive at the time of last follow-up without evidence of disease. Histologically, all tumors were pink at low-power and characterized by a syncytial growth of bland ovoid, spindled, or histiocytoid cells with eosinophilic cytoplasm and prominent perivascular lymphoplasmacytic inflammation. One-third displayed adipocytic metaplasia (8/24). Rare cytologic atypia was seen but was not associated with increased mitotic activity. All tumors expressed S100, SMA, and/or EMA. Keratin expression was absent in most cases. Molecular analysis was performed in 16 cases, all showing EWSR1-rearrangments. In total, 15/15 (100%) harbored an EWSR1::PBX3 fusion, whereas 1 case EWSR1 FISH was the only molecular study performed.

CONCLUSION

Syncytial myoepithelioma is a rare but recognizable morphologic variant of myoepithelioma which may have a predilection for skin but also occurs in diverse non-cutaneous sites. Our series provides evidence supporting a reappraisal of the term "cutaneous syncytial myoepithelioma," as 25% of patients in our series presented with non-cutaneous tumors; thus, we propose the term "syncytial myoepithelioma" to aid pathologist recognition and avoidance of potentially confusing terminology when referring to non-cutaneous examples. The behavior of syncytial myoepithelioma, whether it arises in cutaneous or non-cutaneous sites, is indolent and perhaps benign with a small capacity for local recurrence.

Calcifying fibrous tumor of the mediastinum: A case report

BACKGROUND

Calcifying fibrous tumor (CFT) is a rare benign mesenchymal tumor that often occurs in deep soft tissue of children and young adults. CFT rarely occurs in the mediastinum.

CASE SUMMARY

In this paper, we describe a 31-year-old male patient with CFT in the mediastinum. The patient did not have any symptoms, and the posterior mediastinal lesion was unintentionally found during routine re-examination of thyroid cancer. The tumor had no adhesion to the surrounding tissue and was successfully and completely removed. Pathology showed a large amount of collagen-rich fibrous connective tissue. There was scattered dystrophic calcification and gravel in the fibrous tissue and a small amount of lymphocyte and plasma cell infiltration and lymphoid follicle formation in the interstitial fluid. In addition, findings showed 20 IgG4+ plasma cells per high-powered field of the diseased tissue, an IgG4+/IgG ratio of about 20%, and normal serum IgG4 levels. The final diagnosis was CFT of the mediastinum (CFTM). No evidence of tumor recurrence was observed by computed tomography at 3 mo after surgery.

CONCLUSION

IgG4+ plasma cell enlargement may occur in CFTM, but clinical manifestations and serological tests suggest that it is not IgG4-related disease. We speculate that it may be an independent tumor subtype.

Clinicopathologic Study of Calcifying Fibrous Tumor Emphasizing Different Anatomical Distribution and Favorable Prognosis

Aims

Calcifying fibrous tumor (CFT) is a very rare begin fibroblastic tumor featuring a widely anatomical distribution and may mimic various spindle cell tumors. Misdiagnosis and hence mistreatment are likely caused due to unfamiliarity to clinicians or junior pathologists. We collected a relatively large series of CFTs in our institution aiming at further summarizing their clinicopathologic features in Chinese patients and discussing the diagnosis and differential diagnosis in clinical practice.

Methods

Clinicopathologic data of 22 CFTs were retrospectively reviewed. Histologic features were reevaluated and summarized. Immunostaining markers include CD34, SMA, Desmin, keratin, S100, ALK1, CD117, IgG, IgG4, and Ki-67. Follow-up of all cases was performed.

Results

22 CFTs include gastric (n=8), pulmonary (n=2), hepatic (n=2), cervical (n=1), appendiceal (n=1), esophageal (n=1), retroperitoneal (n=1), intra-abdominal (n=1), diaphragmatic (n=1), spermatic cord and scrotum (n=1), anconeal (n=1), mesenteric (n=1), and omental (n=1) lesions. Coexisting hepatocellular carcinoma, pancreatic carcinoma, pheochromocytoma, Castleman disease, and leiomyoma of the uterus and other metabolic or functional disorders were also appreciated. CFT histologically features spindle cells embedded dense hyalinized stroma with scattered psammomatous calcifications and lymphoplasmacytic infiltration and immunohistochemically for CD34. None of any individuals die of CFT per se.

Conclusion

Our study discloses that CFT is a bona fide benign fibroblastic lesion, regardless of its developing location. Involvement of digestive tract seems much more common in the Chinese population. Awareness of the clinicopathologic characteristics of this rare entity and its mimickers contribute to avoiding misdiagnosis and mistreatment in clinical practice.

Calcifying fibrous tumor and inflammatory myofibroblastic tumor are epigenetically related: A comparative genome-wide methylation study

Based on histological findings, calcifying fibrous tumor (CFT) may be a late (burned out) stage of inflammatory myofibroblastic tumor (IMT). This concept, however, has not been proven by molecular means. Five CFTs were analyzed for IMT-related rearrangements in ALK, ROS1 and RET using fluorescence in situ hybridization (FISH). Additionally, genome-wide methylation patterns were investigated and compared with IMT (n = 7), leiomyoma (n = 7), angioleiomyoma (n = 9), myopericytoma (n = 7) and reactive soft tissue lesions (n = 10) using unsupervised hierarchical cluster analysis and t distributed stochastic neighbor embedding. CFT patients, 4 females and 1 male, had a median age of 20 years ranging from 7 to 43 years. Two patients were younger than 18 years old. The tumors originated in the abdomen (n = 4) and axilla (n = 1). Histologically, all lesions were (multi) nodular and hypocellular consisting of bland looking (myo)fibroblasts embedded in a collagenous matrix with calcifications. FISH analysis brought up negative results for ALK, RET and ROS1 rearrangements. However, genome-wide methylation analysis revealed overlapping methylation patterns of CFT and IMT forming a distinct homogeneous methylation cluster with exception of one case clustering with myopericytoma/angioleiomyoma. In conclusion, DNA methylation profiling supports the concept that CFT and IMT represent both ends of a spectrum of one entity with CFT being the burn out stage of IMT.

Burned-out seminoma revealed by solitary rib bone metastasis

Burned-out tumor is a rare phenomenon in which a testicular tumor regresses in the primary lesion and progresses in a metastatic lesion. We report the case of a 30-year-old male with burned-out seminoma revealed by open biopsy of solitary 10th rib bone metastasis. He underwent inguinal orchiectomy, which revealed hyalinization, indicating a spontaneously regressed testicular tumor. Chemotherapy for seminoma was administered in three cycles of bleomycin + etoposide + cisplatin therapy. The chemotherapy was effective, and wide resection of the rib was subsequently performed. No postoperative chemotherapy was performed, and there has been no evidence of recurrence for 3 years postoperatively.

Calcifying Fibrous Pseudotumor of the Posterior Mediastinum With Encapsulation of the Thoracic Duct

We report the first case of calcifying fibrous pseudotumor (CFPT) to arise in the posterior mediastinum with encapsulation of the thoracic duct. This exceedingly rare lesion was incidentally discovered in an asymptomatic young woman and treated with surgical resection, requiring ligation and excision of the thoracic duct. There has been no evidence of tumor recurrence or postoperative complication.

Clinicopathologic study of calcifying fibrous tumor of the gastrointestinal tract: a case series

Calcifying fibrous tumor (CFT) is a rare benign mesenchymal lesion known to arise at multiple body sites that may clinically mimic other more aggressive lesions in the gastrointestinal (GI) tract. In this study we describe the clinicopathologic findings of 28 GI tract CFTs. Tumors predominantly arose in middle-aged adults with a slight female predominance. The most commonly involved sites were small bowel and colon, followed by stomach and appendix. Tumors ranged from 0.3 to 9.3 cm (median 1.4 cm), and submucosa was the most commonly involved layer. All tumors were well circumscribed and unencapsulated. Microscopically, tumors were hypocellular and composed of spindle cells with abundant, haphazardly arranged hyalinized collagen. No necrosis and less than one mitosis per 10 HPF were identified in all cases. Calcification was present in most (81%) of the cases. All cases had lymphoplasmacytic inflammatory infiltrates either scattered throughout the lesion with occasional perivascular conglomeration or in the form of lymphoid aggregates. A lymphoplasmacytic cuff was usually present (81%). Immunostains showed variable CD34 immunoreactivity and variable numbers of IgG4-positive plasma cells. The lesional cells were negative for DOG-1, ALK-1, S100, C-kit, Sox10, Melan A, HMB45, desmin, CK7, and CK20, and showed cytoplasmic staining for β-catenin. Follow-up information was available in 5 cases with no recurrences reported to date (mean follow-up, 3 years). CFT is a rare benign tumor that can occur in part of the GI tract and should be distinguished from other mesenchymal tumors due to its low risk of recurrence.

Calcifying Fibrous Tumor: Review of 157 Patients Reported in International Literature

Calcifying fibrous tumor (CFT) is a benign lesion characterized by its specific histological findings and is found as solitary or multiple lesions in several locations of the human body. The aim of the present systematic review is to give a detailed account of all reported cases of CFT in the literature and to analyze the available data, to completely characterize the entity from epidemiological, medical, and surgical aspects.A bibliographic research was performed from 1988 until 2015. A database with the patients' characteristics was made, including sex, age, location of the tumor, symptoms, symptoms duration, size of the tumor, diagnostic methods, treatment, metastasis, and follow-up.A total of 104 articles were identified, reporting 157 cases of CFT. Mean age of patients was 33.58 years and the ratio between men and women was 1:1.27. The most common locations of CFT were stomach (18%), small intestine (8.7%), pleura (9.9%), mesentery (5%), and peritoneum (6.8%). Mean diameter of the tumor was estimated 4.6 cm. The correlations proceeded showed that as age increases, size decreases (P = 0.001) and that the tumor is larger in females (P = 0.027). Kruskal-Wallis test showed that the larger tumors appear in the neck and adrenal gland (P = 0.001). The percentage of asymptomatic patients was 30.57%. Computed tomography and biopsy were the most common tests for the diagnosis of CFT. Open surgical procedure was performed in the majority of cases. The median hospitalization was 6.06 days and the mean follow-up period was 29.97 months. Recurrences were mentioned in 10 of 96 patients with available data. No deaths owing to CFT were mentioned in the literature.CFT should be included in the differential diagnosis of enlarging mass revealed by clinical or imaging examination either incidentally or after specific acute or chronic symptomatology.

[About a case of calcifying fibrous tumor of the pleura]

Calcifying fibrous tumor is a rare soft tissue benign tumor (OMS 2002). Some pleural localisations are described, which affect slightly older individuals than the other soft tissue forms. The calcifying fibrous tumor is included in the 2004 World Health Organization classification of pleural tumors. A pleural tumor located in the right inferior pulmonary lobe is diagnosed in a 59-year-old man. This pleural tumor is macroscopically well-circumscribed. Histologically, the rare spindle tumoral cells are located between bundles of a collagenous tissue, sometimes hyalinized, with psammomatous or dystrophic calcifications. The tumoral cells have a fibrohistiocytic origin. They stain positively for antibodies against vimentin, factor XIIIa, CD68, CD163, CD34. Antibodies against smooth muscle actin, desmin, PS100, ALK1 and EBV are negative. Main differencial diagnoses are other benign pleural tumors (solitary fibrous tumor, inflammatory myofibroblastique tumor), some malignant tumors (desmoplastic malignant pleural mesothelioma) and pleural pseudotumors (calcified pleural plaques, chronic fibrous pleuritis, amylose, hyalinizing granuloma). Our case is the 15th pleural calcifying fibrous tumor being reported.

Calcifying Fibrous Tumor of the Gastrointestinal Tract

Calcifying fibrous tumor is a benign mass lesion classically described as a soft tissue tumor. However, a thorough review of the literature reveals that it can occur virtually anywhere, including the tubular gastrointestinal (GI) tract. Its clinical manifestations are variable in the GI tract, and its imaging findings are nonspecific. However, it has unique histologic and immunophenotypical features that must be recognized by GI pathologists to differentiate it from an assortment of other rare mesenchymal lesions of the abdomen and GI tract. Calcifying fibrous tumor is composed of a paucicellular collagen matrix, interspersed calcified bodies, and a sparse inflammatory infiltrate. Although calcifying fibrous tumor is benign, pathologists must be aware that it may occur in the GI tract to differentiate it from other potentially more aggressive, rare mesenchymal lesions.

Calcifying fibrous tumor: an unrecognized IgG4--related disease?

Calcifying fibrous tumor is a rare benign mass lesion characterized by bland spindle cells embedded in abundant collagenous matrix, interspersed dystrophic or psammomatous calcifications, and lymphoplasmacytic infiltrate. It shares several clinical and morphologic features with IgG4-related disease, a newly recognized fibroinflammatory disorder. Characteristic histologic features of IgG4-related lesions include dense fibrosis and abundant lymphoplasmacytic infiltrate, similar to calcifying fibrous tumor. They contain high numbers of IgG4-positive plasma cells in the tissue. Patients also often have elevated serum IgG4 levels. We report the case of a patient with an ileal calcifying fibrous tumor that contained 69 IgG4-positive plasma cells per high-power field and an IgG4-to-IgG ratio of 56% in lesional plasma cells. The patient's serum IgG4 level was 185 mg/dL, more than double the normal value. Altogether, these features suggest that calcifying fibrous tumor could be an unrecognized lesion of IgG4-related disease.

Calcifying fibrous tumor presenting as rectal submucosal tumor: first case reported in rectum

Calcifying fibrous tumor (CFT) is a recently recognized rare benign lesion characterized by dense hyalinized collagenous tissue with interspersed spindle cells and a lymphoplasmocytic infiltrate. Calcification is the hallmark of CFT and may present in the form of psammomatous bodies or dystrophic calcifications. CFT of the intestinal tract is uncommon and rectal CFT has never been reported. Recently, we experienced a case of CFT found in the rectum of a 36-year-old man. In this study, we described the characteristic histopathological findings with a review of the relevant literature. Although CFT of the intestinal tract as an intrinsic visceral lesion is unusual and clinically unexpected, CFT should be considered in the differential diagnosis of rectal submucosal tumor.

Inflammatory myofibroblastic tumor of the breast coexisting with breast cancer: a case report

BACKGROUND

The inflammatory myofibroblastic tumor (IMT) is an uncommon low-risk lesion with only a few cases described in the literature.

CASE REPORT

Here, we report a unique case of an IMT coexisting with breast cancer. Modified radical mastectomy was performed, followed by TAC chemotherapy (taxotere, adriamycin and cyclophosphamide). At the 2-year follow-up, the patient continues to be disease free.

CONCLUSION

At the preoperative stage, definitive diagnoses of masses are extremely difficult; surgery is advised only after the diagnosis is confirmed by pathological examination.

Inflammatory Myofibroblastic Tumour: Report of a Rare Form with Exclusive Pleural Involvement

Inflammatory myofibroblastic tumour (IMT) is a rare scleroinflammatory lesion, characterized by a myofibroblastic proliferation with inflammatory infiltrates, with many possible locations and diagnosis based on immunohistochemistry. Pleural IMT is uncommon and is usually an extension of a pulmonary involvement. We report on a 28-year-old woman with a new form of this rare entity, characterized by exclusive pleural involvement.

Axillary calcifying fibrous tumor (CFT) in an 8 year old girl

Calcifying fibrous tumors (CFTs) are benign soft tissue masses that can occur at many sites. This case report outlines the diagnostic workup for this rare, fast-growing, solitary mass in an otherwise healthy 8 year old patient. We also describe the radiographic and pathological characteristics unique to this lesion.

Fibroblastic and myofibroblastic tumors in children and adolescents

Fibroblastic and myofibroblastic tumors in children and adolescents are a relatively common group of soft tissue proliferations that range from reactive to hamartomatous to neoplastic, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic and immunohistochemical overlap, despite significant clinical, genetic, and prognostic differences. The fibromatoses are a major subgroup, and all types of fibromatoses can occur in the 1st 2 decades of life. Intermediate and malignant fibroblastic-myofibroblastic tumors are an important group that includes variants of fibrosarcoma and other tumors with recurrent cytogenetic or molecular genetic abnormalities and low metastatic potential. Pathologic examination is enhanced by adjunct techniques, such as immunohistochemistry, cytogenetics, and molecular genetics, although morphology provides the ultimate criteria for a specific diagnosis. This article reviews the clinicopathologic features of fibroblastic and myofibroblastic tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents, the use of diagnostic adjuncts, and differential diagnoses.

Soft-tissue inflammatory myofibroblastic tumors (IMTs) of the limbs: potential and limits of diagnostic imaging

OBJECTIVE

The objective of this work was to evaluate the potential of diagnostic imaging in the identification, localization, and characterization of soft-tissue inflammatory myofibroblastic tumors (IMTs) of limbs with correlation to differential diagnosis and therapy.

MATERIALS AND METHODS

From a retrospective analysis of 324 histologically verified soft-tissue lesions of limbs and extremities diagnosed in our institute from January 2002 to July 2010, we selected seven cases of histologically proven IMT. These included six males and one female, aged between 28 and 81 years (mean age, 57 years). Lesions were localized in three cases to the thigh, in two cases to the popliteal space, and in the remaining two cases, to the shoulder girdle. All patients were evaluated on the basis of US, CT, and MRI.

RESULTS

Ultrasound detected the presence of a non-homogeneous solid formation in all cases and calcifications in three cases. CT showed the presence and type of calcification/ossification and bone reaction. On MRI, all cases had low signal intensity on SE T1-weighted sequences and an intermediate-low signal intensity on SE and FSE T2-weighted sequences in six of them; only one case had an intermediate-high signal intensity on SE and FSE T2-weighted sequences. Both contrast-enhanced CT and MRI showed precocious enhancement in association with multiple peripheral hypertrophic blood vessels.

CONCLUSIONS

On the basis of integrated imaging data obtained by US, CT, and MRI, it is possible to evaluate the lesion extension to provide a loco-regional staging, to characterize IMTs, and to allow an optimal therapeutical planning.

Calcifying fibrous tumor of the spine

OBJECTIVE

Calcifying fibrous tumor is a rare, benign soft-tissue tumor of unknown etiology, characterized by hyalinized collagenous fibrous tissue with psammomatous or dystrophic calcification and focal lymphoplasmacytic infiltrate known to involve different organ systems. Involvement of the spine and the presence of metaplastic ossification previously have not been reported.

INTERVENTION

We report a 44-year-old female with progressive nontraumatic flank pain. Imaging revealed a left-sided retroperitoneal calcified mass attached to L5 body with no evidence of extension into the neural foramina, nearby vascular structures, or psoas muscle. The patient had an en bloc resection of the tumor via the transabdominal approach. A pathologic diagnosis of calcifying fibrosis with metaplastic ossification of the spine was reported. Postoperative recovery was uneventful and there is no recurrence after 18 months of follow-up.

CONCLUSION

Calcifying fibrous tumor, a rare benign soft tissue tumor must be considered in the differential diagnosis of a retroperitoneal calcified mass closely associated with the spinal column. Spine surgeons should be aware of this rare pathologic disease entity and although its natural history is not clear, marginal excision is usually adequate.

Bilobular calcifying fibrous pseudotumor in soleus muscle: a case report

Introduction

Calcifying fibrous pseudotumor is a rare benign soft-tissue lesion composed of fibrous tissue with abundant hyalinized collagen and dystrophic and often psammomatous calcifications. The cause of the disease is unclear but, usually, complete resection of the well-circumscribed tumor is sufficient to avoid recurrence of the disease. Here, we report an unusual case of this rare tumor that presented as two lobulated lesions in the calf muscle.

Case presentation

The patient was a 17-year-old Japanese girl who noted a hard mass in her left calf. Magnetic resonance imaging revealed two well-demarcated lobular masses in the soleus muscle, and the tumor was significantly enhanced by contrast medium. Preoperative differential diagnoses included soft-part tumors composed of fibrous tissue. However, making a definite diagnosis was impossible because a lobulated shape is rare for fibrous tumors. Biopsy demonstrated that the mass was a benign tumor composed of collagen-rich, hyalinized fibrosclerotic tissue. We performed marginal resection of the two nodules, including the fibrous tissue that connected them. Immunohistochemistry was positive for factor XIIIa and negative for anaplastic lymphoma kinase-1. These findings were helpful to distinguish calcifying fibrous pseudotumor from inflammatory myofibroblastic tumor. There was no sign of recurrence at 30 months after surgery.

Conclusion

To the best of our knowledge, this is the first case of bilobular calcifying fibrous pseudotumor that developed in an extremity. As described in the previous literature, simple excision was sufficient for the treatment of calcifying fibrous pseudotumor with two lobules.

Disseminated calcifying tumor of the pleura: review of the literature and a case report with immunohistochemical study of its histogenesis

Calcifying tumor of the pleura is a rare benign tumor, similar to the calcifying fibrous pseudotumor originally described in the subcutaneous and deep soft tissues of the extremities, trunk, and neck. Calcifying tumors of the pleura have also been reported infrequently as disseminated lesions. Here we report a case of disseminated calcifying tumor of the pleura, with some new findings obtained in this study, and review the literature of disseminated calcifying tumor of the pleura.

Multifocal peritoneal calcifying fibrous tumour: incidental finding at cholecystectomy

Calcifying fibrous tumour (CFT) is a benign tumour of elusive aetiology and a potential for local recurrence. Despite its peculiar histological characteristics it can still be confused with interrelated differential diagnosis like inflammatory myofibroblastic tumour (IMT) or solitary fibrous tumours. The clinical differential diagnosis is however much wider. To date seven cases of multiple peritoneal CFTs are on record. The authors present a case discovered incidentally during laparoscopic cholecystectomy, with no previous history and no radiological diagnosis achieved despite having undergone magnetic resonance cholangiopancreatography (MRCP) and normal routine perioperative investigation. The patient is disease-free 12 months after diagnosis. The case report is followed by a detailed literature review.

Calcifying fibrous tumor of the stomach: clinicopathologic and molecular study of seven cases with literature review and reappraisal of histogenesis

Calcifying fibrous tumor (CFT) is a rare benign mesenchymal tumor composed of hyalinized fibrous tissue with interspersed bland fibroblastic spindled cells, scattered psammomatous, and/or dystrophic calcifications and variably prominent mononuclear inflammatory infiltrate. CFTs show a predilection for the abdominal cavity and soft tissue. To date, 6 gastric and 3 intestinal CFTs have been reported. We analyzed 7 gastric CFTs including 6 new cases. Patients were 4 men and 3 women with a mean age of 53 years (range, 40 to 77). Mean tumor size was 2.2 cm. Most tumors originated in the gastric body (6/7). Six were incidental findings at autopsy or during surgery for other diseases. One ulcerated tumor caused iron deficiency anemia and ulcer symptoms. Six tumors involved the muscularis propria with variable submucosal and subserosal extension and 1 arose within thickened muscularis mucosae adjacent to a mucosal invagination. Histology was typical with uniformly hypocellular vaguely storiform collagen, lymphoplasmacytic infiltrates, lymphoid aggregates and psammomatous, and dystrophic calcifications. Peritumoral lymphoid aggregates were seen in 3 cases. Adjacent muscle coat contained lymphoid aggregates with fiber degeneration (2), minute CFT-like foci (1), and calcifications (1). In none of the cases were there remnants of burnt-out GIST, inflammatory fibroid polyp, inflammatory myofibroblastic tumor, leiomyoma, schwannoma, or other specific lesion. All tumors were negative for CD117, S100, smooth muscle actin, desmin, ALK1, h-caldesmon, and PDGFRA. Two stained focally with CD34. Scattered IgG4-positive plasma cells were seen in 4 of 6 cases stained with this marker. All 5 tumors with available tissue for molecular analysis were wild-type for KIT and PDGFRA. Three patients had follow-up (range, 12 to 24 mo); none developed recurrence. Gastric CFTs are distinct from sclerosing GIST and other mesenchymal gut lesions and may represent a localized inflammatory fibrosclerosis in response to immune-mediated or other-type tissue injury affecting the muscularis propria. They differ from soft tissue CFTs by smaller size, older age at presentation and lack of recurrence, and from peritoneal CFTs by equal gender distribution, older age, and absent multifocal occurrence.

Anaplastic lymphoma kinase: role in cancer pathogenesis and small-molecule inhibitor development for therapy

Anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase in the insulin receptor superfamily, was initially identified in constitutively activated oncogenic fusion forms - the most common being nucleophosmin-ALK - in anaplastic large-cell lymphomas, and subsequent studies have identified ALK fusions in diffuse large B-cell lymphomas, systemic histiocytosis, inflammatory myofibroblastic tumors, esophageal squamous cell carcinomas and non-small-cell lung carcinomas. More recently, genomic DNA amplification and protein overexpression, as well as activating point mutations, of ALK have been described in neuroblastomas. In addition to those cancers for which a causative role for aberrant ALK activity is well validated, more circumstantial links implicate the full-length, normal ALK receptor in the genesis of other malignancies - including glioblastoma and breast cancer - via a mechanism of receptor activation involving autocrine and/or paracrine growth loops with the reported ALK ligands, pleiotrophin and midkine. This review summarizes normal ALK biology, the confirmed and putative roles of ALK in the development of human cancers and efforts to target ALK using small-molecule kinase inhibitors.

Oral calcifying fibrous pseudotumor: case analysis and review

Calcifying fibrous pseudotumor (CFT) is a rare distinct soft-tissue lesion characterized histologically by lymphoplasmacytic aggregates in a rich collagenized background with abundant psammomatous and dystrophic calcifications. Occurring most often in children and young adults, CFTs are clinically benign lesions that can form over a broad anatomic distribution, including in subcutaneous and deep soft tissues, as well as in serosal and visceral locations. The cause and mechanisms of pathogenesis of CFT are unknown. Simple excision with a margin of normal tissue is the treatment of choice. The risk for local recurrence is low. In this article, we describe a case of CFT in a 29-year-old woman with a 7-cm mass on the right upper gingiva and hard palate, discuss the differential diagnosis with other oral spindle cell lesions, such as, desmoid fibromatosis, nodular fasciitis, inflammatory myofibroblastic tumors, solitary fibrous tumor and also review the recent literature on this rare benign entity.

Development of anaplastic lymphoma kinase (ALK) small-molecule inhibitors for cancer therapy

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase (RTK) involved in the genesis of several human cancers; indeed, ALK was initially identified in constitutively activated and oncogenic fusion forms--the most common being nucleophosmin (NPM)-ALK--in a non-Hodgkin's lymphoma (NHL) known as anaplastic large-cell lymphoma (ALCL) and subsequent studies identified ALK fusions in the human sarcomas called inflammatory myofibroblastic tumors (IMTs). In addition, two recent reports have suggested that the ALK fusion, TPM4-ALK, may be involved in the genesis of a subset of esophageal squamous cell carcinomas. While the cause-effect relationship between ALK fusions and malignancies such as ALCL and IMT is very well established, more circumstantial links implicate the involvement of the full-length, normal ALK receptor in the genesis of additional malignancies including glioblastoma, neuroblastoma, breast cancer, and others; in these instances, ALK is believed to foster tumorigenesis following activation by autocrine and/or paracrine growth loops involving the reported ALK ligands, pleiotrophin (PTN) and midkine (MK). There are no currently available ALK small-molecule inhibitors approved for clinical cancer therapy; however, recognition of the variety of malignancies in which ALK may play a causative role has recently begun to prompt developmental efforts in this area. This review provides a succinct summary of normal ALK biology, the confirmed and putative roles of ALK fusions and the full-length ALK receptor in the development of human cancers, and efforts to target ALK using small-molecule kinase inhibitors.

Application of immunohistochemistry to soft tissue neoplasms

CONTEXT

Soft tissue tumors are composed of numerous and complex diagnostic entities. Because of this complexity and the recognition of an intermediate malignancy category including some tumors with a deceptively bland histologic appearance, soft tissue tumors may represent a major diagnostic challenge to the general practicing pathologist.

OBJECTIVE

To correctly diagnose soft tissue tumors with the ancillary use of immunohistochemistry.

DATA SOURCES

Review of the current literature with emphasis on those tumors for which immunohistochemistry has proven to be particularly useful.

CONCLUSIONS

Immunohistochemistry plays an important role in the diagnosis of soft tissue tumors. One of its major utilities is to correctly identify a tumor as being of mesenchymal or nonmesenchymal origin. Once mesenchymal origin has been established, histologic subtyping according to specific cell lineage may be achieved with the use of lineage-specific markers. Tumors of uncertain cell lineage and tumors with primitive small round cell morphology are often characterized by a unique immunohistochemical phenotype. In this group of tumors, immunohistochemistry is most widely applied and is of greatest value. Despite the rapid development of molecular genetic techniques, immunohistochemistry still remains the most important diagnostic tool in the diagnosis of soft tissue tumors aside from recognition of morphologic features and clinical correlation.

[Gastric calcifying fibrous pseudotumor, a rare mesenchymal tumor of the stomach]

We report a case of calcifying fibrous pseudotumor fortuitously discovered on abdominal CT-scan in a 50 year-old woman presenting with metrorragia. CT-scan showed a 2 cm hypodense nodular tumor of the gastric wall with granular calcifications. Upper endoscopy showed a nodular tumor along the lesser curvature of the gastric body, covered by normal gastric mucosa and biopsies were negative. A diagnosis of gastric stromal tumor was suspected and a partial gastrectomy was performed. On gross examination surgical specimen showed a firm, whitish nodular tumor measuring 2 cm in diameter. On microscopic examination the tumor was composed of whorls of dense hyalinized collagen bundles with a few fibroblasts. There were psammomatous calcifications and nodular aggregates of mononuclear inflammatory cells. Immunohistochemically, spindle cells stained for vimentin. They did not stain for smooth muscle actin, desmin, CD34, CD117, S100 protein, Ki-67 and ALK-1. Surgical resection of the tumor was complete. Patient has no evidence of disease with a follow-up of 12 months. Only seven cases of gastric calcifiying fibrous pseudotumors have been reported in the literature. These benign tumors are usually incidentally discovered. They have characteristic imaging and microscopic features and appear as a distinct clinicopathologic entity different from stromal tumors.

Calcifying fibrous tumor of small intestine

Calcifying fibrous tumor (CFT) is a rare benign tumor with a predilection for children and young adults that usually arises in the subcutaneous and deep soft tissues, pleura, or peritoneum. It presents histologically as a well-circumscribed mass consisting of hyalinized, hypocellular lamellar collagen, bland spindle cells, chronic inflammatory cell infiltrates, and psammomatous or dystrophic calcifications. Calcifying fibrous tumor of the gastrointestinal tract is exceedingly rare and therefore prone to confusion with other spindle cell lesions more commonly encountered in this location. We describe 4 cases of calcifying fibrous tumor arising in the terminal ileum, one of which caused the heretofore unreported complication of intestinal intussusception, and discuss the differential diagnosis with other common and uncommon spindle cell lesions.

Multiple peritoneal calcifying fibrous tumors revealed by ischemic colitis

We report the case of a 41-year-old man presenting with multiple calcifying fibrous tumor (CFT) revealed by ischemic colitis. Peritoneal nodular lesions involved omental, mesenteric, mesorectal, and mesocolic serosal surfaces. Histologically, nodules were composed of dense bundles of collagen, calcifications, and lymphoplasmacytic infiltrate. These findings were diagnostic of CFTs, a rare and often asymptomatic benign fibrous process. Multiple peritoneal CFTs are very uncommon and usually occur in women. Calcifying fibrous tumors are usually cured by surgical excision. The differential diagnosis and histogenesis of this entity are discussed.

Gastrointestinal stromal tumors: diagnostic challenges and practical approach to differential diagnosis

Over the last decade, gastrointestinal stromal tumors (GISTs) have evolved from histogenetically obscure gastrointestinal mesenchymal tumors to well-defined tumors with distinctive clinical, morphologic, ultrastructural, histogenetic, and molecular characteristics, for which targeted therapy is available. This is largely attributable to the discovery of CD117 overexpression and activating mutations in c-kit or platelet-derived growth factor alpha genes in most of GISTs. The availability of specific diagnostic tests and targeted therapy for GISTs has led to an increased awareness of these tumors. At the same time, the list of potential GIST mimics has lengthened considerably and it has become increasingly important that GISTs be distinguished from their mimics because correct diagnosis has implications for both treatment and prognosis. The purpose of this review is to provide an update of the expanding differential diagnosis of GISTS, to draw attention to unusual GIST variants, to provide a practical approach the differential diagnosis of GISTs and to highlight some of the challenges faced by pathologists in resolving this differential diagnosis.

Inflammatory myofibroblastic tumors of the urinary tract: a clinicopathologic study of 46 cases, including a malignant example inflammatory fibrosarcoma and a subset associated with high-grade urothelial carcinoma

Inflammatory myofibroblastic tumor (IMT) of the urinary tract, also termed postoperative spindle cell nodule, inflammatory pseudotumor, and pseudosarcomatous fibromyxoid tumor, is rare and in the past was believed to reflect diverse entities. We reviewed a series of 46 IMTs arising in the ureter, bladder, and prostate, derived primarily from a large consultation practice. There were 30 male and 16 females aged 3 to 89 years (mean 53.6). Lesions were 1.2 to 12 cm (mean 4.2). There was a history of recent prior instrumentation in 8 cases. Morphology was similar to that previously described for IMT occurring in this region, with the exception of 1 case that focally appeared sarcomatous. Polypoid cystitis coexisted in 5 patients (11%). Mitoses were typically scant (0 to 20/10 hpf, mean 1). Necrosis was seen in 14 (30%) cases. Invasion of the muscularis propria was documented in 19 (41%). By immunohistochemistry (IHC), lesions at least focally expressed anaplastic lymphoma kinase (ALK) (20/35, 57%), AE1/3 (25/34, 73%), CAM5.2 (10/15, 67%), CK18 (6/6, 100%), actin (23/25, 92%), desmin (15/19, 79%), calponin (6/7, 86%), caldesmon (4/7, 57%, rare cells), p53 (10/13, 77%), and most lacked S100 (0/14), CD34 (0/13), CD117 (2/13, 15%), CD21 (0/5), and CD23 (0/3). ALK gene alterations were detected by fluorescence in situ hybridization (FISH) in 13/18 (72%) tested cases, including 2 with prior instrumentation; 13/18 (72%) showed agreement between FISH ALK results and ALK protein results by IHC. Most bladder IMTs were managed locally, but partial cystectomy was performed as the initial management in 7 cases and cystectomy in 1 (1 IMT was initially misinterpreted as carcinoma, 1 IMT was found incidentally as a separate lesion in a cystectomy specimen performed for urothelial carcinoma). Follow-up was available in 32 cases (range 3 to 120 mo; mean 33; median 24). There were 10 patients with recurrences (2 with 2 recurrences). Recurrences were unassociated with muscle invasion or with ALK alterations. In 2 cases, tumors of the urinary tract (TURs) showing IMT preceded (1 and 2 mo, respectively) TURs showing sarcomatoid carcinoma with high-grade invasive urothelial carcinoma accompanied with separate fragments of IMT. Even on re-review the IMT in these 2 cases were morphologically indistinguishable from other cases of IMT, with FISH demonstrating ALK alterations in the IMT areas in one of them. Both these patients died of their carcinomas. Lastly, there was 1 tumor with many morphological features of IMT and an ALK rearrangement, yet overtly sarcomatous. This case arose postirradiation for prostate cancer 4 years before the development of the lesion, with tumor recurrence at 4 months and death from intra-abdominal metastatic disease at 9 months. In summary, urinary tract IMTs are rare and share many features with counterparts in other sites, displaying similar morphology and immunogenotypic features whether de novo or postinstrumentation. Typical IMTs can be locally aggressive, sometimes requiring radical surgical resection, but none of our typical cases metastasized, although they can rarely arise contemporaneously with sarcomatoid urothelial carcinomas. For these reasons, close follow-up is warranted.

Calcifying fibrous tumor of the adrenal gland

Calcifying fibrous tumor is an uncommon entity with distinctive pathologic features. Most calcifying fibrous tumors involve the peripheral soft tissues or serosal surfaces, with reports of visceral examples of this lesion being extremely limited. We report the clinical and pathologic features of an unusual case of calcifying fibrous tumor occurring in the adrenal gland of a 32-year-old woman. Microscopically, the lesion was well circumscribed and composed of dense, poorly cellular collagenous tissue, scattered spindle cells, an inflammatory infiltrate consisting of plasma cells and lymphocytes, and dystrophic calcifications. The morphologic diagnosis of calcifying fibrous tumor was supported by diffuse positive immunoreactivity for factor XIIIa and absence of reactivity for muscle specific actin, smooth muscle actin, and anaplastic lymphoma kinase. Although rare, awareness that calcifying fibrous tumor may occur at this particular site is important so as not to confuse this lesion with other mesenchymal neoplasms of the adrenal gland.

Calcifying fibrous pseudotumor of the myocardium

Calcifying fibrous pseudotumor is an uncommon tumor first described in 1988 as a childhood fibrous tumor with psammoma bodies. The typical pathological findings are those of a densely collagenized fibrous tumor with psammomatous and dystrophic calcification accompanied by a lymphoplasmacytic infiltrate. To date these tumors are reported in subcutaneous and deep soft tissues of the extremities and trunk, groin, scrotum, pleura, mediastinum, paratracheal region, peritoneum, neck, mesentery, omentum, serosa, lung, bone, and gallbladder. We describe a 17-year-old girl with a myocardial calcifying fibrous tumor, and we review the English literature.

Incidental calcifying fibrous tumor of the stomach presenting as a polyp

Calcifying fibrous tumor (CFT) is an uncommon lesion of uncertain cause and pathogenesis that has a unique histological appearance. These lesions are described mainly in the subcutaneous or deep soft tissues, followed by subserosal locations. Intrinsic visceral CFT is extremely rare. Herein is described a rare case of CFT that involved the gastric wall, along with a review of the literature. An incidental small polypoid lesion was excised during urgent surgery for penetrating injury at the lesser curvature in a 25-year-old man, previously healthy. The lesion was a well-demarcated, small (10 mm) tumor that occupied the submucosa. The characteristic histopathological features and the presence of spindle cells that express factor XIIIa allowed a diagnosis of CFT to be made. The present case and the review revealed that, despite their frequent subperitoneal location, intra-abdominal CFT might present as intrinsic visceral lesions and might be found incidentally. These lesions tend to be smaller when compared to their symptomatic counterparts. The diffuse factor XIIIa expression in CFT might be useful to differentiate this entity from other intra-abdominal soft-tissue tumors in problematic cases. Although rarity of intrinsic visceral CFT necessitates new cases to determine their exact biological behavior, the present case highlights their presence in the stomach as a symptomless small polypoid lesion.

Calcifying Fibrous Pseudotumor of the Pleura

Calcifying fibrous pseudotumor is an uncommon benign lesion that has unique histologic features. We report a case of calcifying fibrous pseudotumor of the pleura occurring in a 31-year-old woman. A computed tomographic scan revealed a pleural mass in the right anterior costophrenic angle. The excised mass was well circumscribed, nonencapsulated, solid, and firm. The tumor showed dense hyalinized collagenous tissue interspersed with spindle cells, psammomatous calcifications, and a predominantly lymphoplasmocytic infiltrate. Most spindle cells were diffusely positive for vimentin, focally positive for CD34, and negative for desmins, smooth muscle actin, S-100 protein, and anaplastic lymphoma kinase-1.

Multiple calcifying fibrous tumors of the pleura

Calcifying fibrous tumor (CFT) is a rare lesion characterized histologically by hypocellular hyalinized collagenous tissue with psammomatous and/or dystrophic calcifications and patchy lymphoplasmacytic infiltrates. CFT usually occurs in the somatic soft tissue of children and young adults but is rarely found in the pleura. We describe here an unusual case of multiple small CFTs in the right mediastinal pleura of a 54-year-old man who had a history of renal cell carcinoma. Suspecting pulmonary and pleural metastases, we performed wedge resection of the right middle lobe and local excision of two nodules in the right pleura. Light microscopy revealed metastatic lesions of renal cell carcinoma in the resected wedge. The pleural nodules were well circumscribed and composed of hypocellular, dense, hyalinized, collagenous tissue with scant lymphoplasmacytic infiltration and characteristic psammoma bodies. Immunohistochemical staining revealed that most spindle cells were positive for vimentin, CD34 and factor XIIIa, and negative for epithelial membrane antigen, keratin, smooth-muscle actin, desmin, S-100 protein and anaplastic lymphoma kinase. We made a histological diagnosis of CFT of the pleura, and the patient remains well 6 months after the wedge resection.

Anaplastic lymphoma kinase proteins in growth control and cancer

The normal functions of full-length anaplastic lymphoma kinase (ALK) remain to be completely elucidated. Although considered to be important in neural development, recent studies in Drosophila also highlight a role for ALK in gut muscle differentiation. Indeed, the Drosophila model offers a future arena for the study of ALK, its ligands and signalling cascades. The discovery of activated fusion forms of the ALK tyrosine kinase in anaplastic large cell lymphoma (ALCL) has dramatically improved our understanding of the pathogenesis of these lymphomas and enhanced the pathological diagnosis of this subtype of non-Hodgkin's lymphoma (NHL). Likewise, the realisation that a high percentage of inflammatory myofibroblastic tumours express activated-ALK fusion proteins has clarified the causation of these mesenchymal neoplasms and provided for their easier discrimination from other mesenchymal-derived inflammatory myofibroblastic tumour (IMT) mimics. Recent reports of ALK expression in a range of carcinoma-derived cell lines together with its apparent role as a receptor for PTN and MK, both of which have been implicated in tumourigenesis, raise the possibility that ALK-mediated signalling could play a role in the development and/or progression of a number of common solid tumours. The therapeutic targeting of ALK may prove to have efficacy in the treatment of many of these neoplasms.