Angiomatoid fibrous histiocytoma: a series of seven cases including genetically confirmed aggressive cases and a literature review

Angiomatoid fibrous histiocytoma: primary intracranial lesion with thoracic spine metastasis and a malignant course. Illustrative case

BACKGROUND

Angiomatoid fibrous histiocytoma (AFH) is an exceptionally rare soft tissue neoplasm. This tumor primarily presents as a benign soft tissue lesion in children with an average age of 14 years. The standard treatment regimen is wide local excision with interval follow-up. However, newer reports have demonstrated malignant potential with the possibility of intracranial metastasis.

OBSERVATIONS

A 45-year-old male with no soft tissue primary tumor presented with a primary intracranial lesion and thoracic spine metastasis refractory to chemotherapy and radiation treatment.

LESSONS

This report illustrates the potential for a highly malignant nature of metastatic AFH. In addition, the authors demonstrate an incidence of AFH in a middle-aged male without a primary soft tissue or skin lesion. This report highlights the importance of prompt treatment and excision for AFH, as there is still little understanding of successful options for systemic therapy.

Case Report: Angiomatoid fibrous histiocytoma in the hand: a rare clinical presentation and diagnostic challenge

Angiomatoid fibrous histiocytoma (AFH) is a rare tumor of mesenchymal origin occurring in young adults. Based on its clinical course, it is said to have an intermediate potential. We present a case of a 59-year-old woman with AFH in the hand that was difficult to diagnose. A benign soft tissue tumor was suspected on magnetic resonance imaging, and its size and open biopsy suggested nodular fasciitis or inflammatory myofibroblastic tumor. A diagnosis of AFH was eventually made based on the analysis of the resected specimens. The characteristic findings of histopathology and immunohistochemistry in this case were relatively poor, so fluorescence in situ hybridization contributed to making the correct diagnosis. Considering its prognosis, careful follow-up was decided upon without additional surgery. Our case is a challenging one because of its atypical presentation and inconclusive imaging and histopathological findings.

Difficulties in diagnosing angiomatoid fibrous histiocytoma of the head and neck region: A case report

BACKGROUND

Angiomatoid fibrous histiocytoma (AFH) is a rare, slow-growing soft tissue tumor. It appears mostly on the limbs and trunk in children and young adults. The biology of AFH remains unclear because of the small number of reported cases. Diagnostic testing does not provide definitive results. It has two clinical forms, that differ in terms of gene expression and clinical prognosis. It is important to inform the laboratory which specific gene testing is necessary. Here, we describe a case of rare AFH in the submandibular region using a full genetic panel.

CASE SUMMARY

A 13-year-old boy who had been misdiagnosed in the past 6 mo by his dentist visited our clinic because of a lesion in the submandibular area on the right side. The lesion was homogeneous and painless upon palpation. No skin discoloration was observed. Due to the non-specific radiological picture computed tomography (CT), magnetic resonance imaging (MRI), cone-beam CT (CBCT), and ultrasound-guided biopsy were performed. A venous malformation was suspected on the MRI. None of the tests provided a definitive diagnosis. Owing to the non-specific radiological findings, the patient qualified for surgical treatment. The surgical procedure included an excisional biopsy. The diagnostic testing was extended using gene rearrangements. The most distinctive gene translocation in diagnosing AFH is within the EWS RNA-binding protein 1 (EWSR1)-CREB-binding protein. However, in this case, the diagnosis was confirmed by a rearrangement within the EWSR1 gene testing.

CONCLUSION

AFH in the submandibular location is rare, and surgical treatment with genetic evaluation defines AFH type that affects subsequent procedures.

Pulmonary Metastasising Aneurysmal Fibrous Histiocytoma: A Case Report, Literature Review and Proposal of Standardised Diagnostic Criteria

An aneurysmal fibrous histiocytoma is a rare cutaneous soft-tissue tumour which accounts for approximately 0.06% of all dermatopathologies. Metastasis is exceedingly uncommon, to the point that there have only been eight reported cases in the scientific literature. We present the case of a 25-year-old male with a primary aneurysmal fibrous histiocytoma located in the nuchal region which exhibited rapid growth and abrupt ulceration over a short time span and showed signs of locoregional aggressive infiltration. A subsequent histopathological analysis confirmed the presence of diffuse solid and cystic pulmonary metastases. Further genetic sequencing verified LAMTOR1-PRKCD fusion. This case report seeks to review the existing literature on aneurysmal fibrous histiocytoma, discuss the challenges of differential diagnosis and propose standardised diagnostic criteria.

Unusual case of inflammatory rhabdomyoblastic tumor in a pediatric patient

Inflammatory rhabdomyoblastic tumor (IRMT) is a rare, recently described skeletal muscle neoplasm of uncertain malignant potential. We report an unusual tumor in the right arm of a 5-year-old boy, which is the first case of a pediatric IRMT. Immunohistochemically, most cells in the tumor were positive for CD163 and CD68 staining. The neoplastic cells themselves showed a skeletal muscle phenotype with a diffuse expression of desmin and a focal expression of myoD1. Mitotic activity was low (1/10 HPF), and no necrosis was observed.

Evidence of Chemoresponsiveness in Unresectable Metastatic Angiomatoid Fibrous Histiocytoma

Angiomatoid fibrous histiocytoma (AFH) is a soft tissue neoplasm of intermediate biological potential. Typically a slow-growing tumor, it can recur locally. Rarely, it manifests as a soft tissue sarcoma capable of metastasis. When metastases are nonamenable to local therapy, it is believed uniformly fatal. We present 3 patients with metastatic AFH who demonstrated a sustained response to chemotherapy; including one who achieved complete remission with cryoablation. These cases reinforce the potential value of chemotherapy in some patients with unresectable metastatic AFH and provide the first case in the literature of cryoablation in AFH.

Review of primary superficial soft tissue mesenchymal tumors of malignant or intermediate biological potential

The majority of the sarcomas are deep in location, larger than 5 cm in size, and heterogenous in imaging appearance. However, when sarcomas occur superficially, these typical features may be absent, failing to alert the radiologist to a malignancy and mimicking one of the more numerous benign superficial tumors that make up the bulk of soft tissue mass evaluations. This manuscript will discuss the current role of imaging in recognizing features concerning for superficial soft tissue sarcomas. Provided is an overview of the demographic, clinical, and imaging features of the most commonly encountered superficial soft tissue sarcomas, including undifferentiated pleomorphic, leiomyosarcoma, synovial sarcoma, liposarcoma, myxofibrosarcoma, dermatofibrosarcoma protuberans, epithelioid sarcoma, and angiosarcoma. A less common but primary superficial tumor, angiomatoid fibrous histiocytoma, is also reviewed as the diagnosis may be confounding both clinically and on imaging studies.

Angiomatoid Fibrous Histiocytoma in an Elderly Male: An Unusual Presentation of a Rare Case

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue neoplasm of low malignant potential often misdiagnosed clinically. It typically occurs in the superficial soft tissues of the extremities in children and young adults. It is characterized by recurrences and rarely metastases. Surgery remains the mainstay of management. Here, we present a rare case report of AFH in a 65-year-old male diagnosed using fine needle aspiration as spindle cell sarcoma. The patient underwent wide local excision. The patient is under follow-up. There is no evidence of metastases, and the patient is disease free three-years post-excision.

The utility of TLE1 and BCOR as immunohistochemical markers for angiomatoid fibrous histiocytoma

OBJECTIVES

Diagnosis of angiomatoid fibrous histiocytoma (AFH) can be challenging due to its variable histologic features and a lack of highly sensitive and/or specific immunohistochemical markers. The utility of TLE1 and BCOR as immunohistochemical markers for AFH is not known.

METHODS

We examined the spectrum of histologic features of 36 AFHs, and studied the expression of both TLE1 and BCOR in AFH and its mimics by immunohistochemical staining. Positive nuclear expression was scored semiquantitatively.

RESULTS

Both typical and unusual histologic features of AFHs were observed in this cohort. TLE1 was moderately to strongly positive in 36/36 AFHs, 4/4 synovial sarcomas, and 2/3 BCOR sarcomas; weakly positive in 4/6 inflammatory myofibroblastic tumors; negative in all dermatofibromas (n = 10), atypical fibrous histiocytomas (n = 5), myofibroma (n = 2) and juvenile xanthogranulomas (n = 5), with an overall sensitivity of 100%, and specificity of 71.4% for AFH. BCOR was moderately to strongly positive in 24/36 AFHs, 4/4 synovial sarcomas, 3/3 BCOR sarcomas, and 1/5 atypical fibrous histiocytomas; weakly positive in 10/36 AFHs; negative in the remaining tumors. The overall sensitivity and specificity of BCOR for AFH were 94.4% and 77.1%, respectively.

CONCLUSIONS

TLE1 is a highly sensitive immunohistochemical marker for AFH.

Pulmonary Artery Angiomatoid Fibrous Histiocytoma Mimicking a Large Pulmonary Embolism

ABSTRACT

A 39-year-old man presented with progressive dyspnea and lower extremity edema. Doppler ultrasound demonstrated bilateral leg partially occluded venous thromboses. A V/Q scan revealed a mismatched perfusion defect involving the entire right middle and lower lobes. Subsequent CT pulmonary angiogram revealed a mass lesion occluding the right interlobar pulmonary artery. Endobronchial ultrasound-guided fine-needle aspiration of the mass was concerning for neoplasm. 18 F-FDG PET/CT demonstrated marked hypermetabolism of the mass lesion. Patient underwent transmediastinal right pneumonectomy with histopathologic diagnosis of pulmonary artery angiomatoid fibrous histiocytoma, a rare etiology mimicking large pulmonary artery embolism.

Angiomatoid Fibrous Histiocytoma (AFH) of the Right Arm: An Exceptional Case with Pulmonary Metastasis and Confirmatory EWSR1::CREB1 Translocation

Angiomatoid fibrous histiocytoma (AFH) is a rare neoplasm described for the first time by Enzinger in 1979, and classified by World Health Organization 2020 as intermediate malignant potential neoplasm. It mostly occurs in the subcutis and is characterized by varying proportions of epithelioid, ovoid and spindle cells in a nodular and syncytial growth pattern, with some hemorrhagic pseudovascular spaces. In this paper, we report the clinical case of a 62-year-old man who presented with AFH on the right arm, and relapsed three years after first surgical excision. After a further three years, the patient presented with an intramuscular localization of AFH, and 12 months after this, a pulmonary metastasis of AFH was diagnosed. Given the rarity of the spreading of AFH, we performed Fluorescence In Situ Hybridization (FISH) and we detected EWSR1::CREB1 gene fusion.

Brain parenchymal angiomatoid fibrous histiocytoma and spinal myxoid mesenchymal tumor with FET: CREB fusion, a spectrum of the same tumor type

Angiomatoid fibrous histiocytomas (AFH) is a rare soft tissue tumor of intermediate malignant potential, and its histology is diverse. It can occur in several organs including intracranial and soft tissues. Here, we report two cases of brain parenchymal classic AFH and spinal extramedullary myxoid mesenchymal tumor with clinicopathological and molecular investigations by next-generation sequencing and a comprehensive review. The current brain parenchymal AFH occurred in a 79-year-old woman, and the spinal myxoid mesenchymal tumor arose in the thoracic spine of a 28-year-old woman; both harbored FET:CREB fusion. The current brain parenchymal AFH has not recurred for 15-months follow-up period, but the spinal myxoid mesenchymal tumor recurred three times and metastasized to T8 spine level for 30-months follow-up period. We reviewed 40 reported cases of central nervous system (CNS) AFHs/myxoid mesenchymal tumors including our two cases to identify clinicopathological features and biological behaviors. They occur with a slight female predominance (M:F = 1:1.7) in children and young adults (median age: 17 years; range: 4-79 years old). Approximately 80% of CNS AFHs were younger than 30 year. Most of them were dura-based and were not just intracranial tumors as they occurred anywhere in the CNS including spinal dura. EWSR1 rearrangement was the most common driver (98%), including FET:CREB (33%), EWSR1:ATF1 (30%), and EWSR1:CREM (27%) fusions, but FUS:CREM fusion (2%) was also present. During the follow-up period (median: 27 months), 43% (17/40) of CNS AFHs recurred between two months and 11 years, and multiple recurrences were also observed. One case showed metastases to the lymph nodes and vertebrae, and among 11 cases that resulted in death, four cases provided available clinical data. Because these tumors are identical to soft tissue AFH or primary pulmonary myxoid sarcoma with an FET:CREB fusion in morphological and immunohistochemical spectra, the authors propose incorporating the two tumor terms into one.

Malignant Superficial Mesenchymal Tumors in Children

Malignant superficial mesenchymal tumors are a very diverse group of neoplasms with few clinical and radiological discriminatory factors. Hence, some of these cancers are rarely suspected based on clinical and radiological grounds, others may be easily misdiagnosed, and the histological analysis of a biopsy or resection is central in the diagnostic process. In children, the age at presentation is a major element of the differential diagnosis. Some tumors have a very distinct epidemiology, while others may be seen at any age. More recently, the advances in molecular biology have greatly improved the diagnosis of mesenchymal tumors and new entities are still being described. In the present review, we provide an overview of the diversity of malignant superficial mesenchymal tumors in children, including new and/or rare entities. We discuss the important diagnostic features, be they clinical, histological, or molecular. Special attention was given to the genetic features of these tumors, particularly when they were helpful for the diagnosis or treatment.

Angiomatoid Fibrous Histiocytoma Mimicking a Lymph Nodal Lesion: A Case Report

Angiomatoid fibrous histiocytoma is an uncommon soft tissue neoplasm with potential for recurrence and rare metastasis. The majority of cases are painless, slow growing and occur in superficial extremities of young adults. Here we report a case of Angiomatoid fibrous histiocytoma in a 28-year-old male patient presenting as a slowly growing painful mass in the groin region. This case is of particular interest due to its uncommon site of presentation and its misdiagnosis as lymph nodal lesion on radiology. Although it is a rare entity, it should be considered in differential diagnosis of soft tissue mass in a young patient.

Intracranial angiomatoid fibrous histiocytoma: report of a rare case

One rare and low-grade soft tissue tumor with intermediate malignant potential is angiomatoid fibrous histiocytoma (AFH)و which occurs mainly in children and adolescents. The tumor naturally tends to local recurrence and recurrent hemorrhage but rarely to remote metastasis. AFH has been reported in different organs; however, there are rare reports of primary intracranial AFH. The diagnosis of AFH may be difficult due to its occurrence at multiple unusual anatomic sites and its spectrum of morphologic patterns; thus, it is especially important to diagnose it correctly because of the small risk of metastasis and death. The lesion is simply confused with a hematoma, soft tissue hemangioma, or malignant fibrous histiocytoma from clinical and radiographical aspects. We report a case of intracranial AFH in a 5-year-old boy. The tumor is a heterogeneous intra-axial with a size of 78*73mm at the right front temporal. There was also an extra-axial mass measured 8*12mm at the left superior frontal lobe in favor of metastasis. The diagnosis was confirmed using radiographical, immunohistochemical, and molecular tests. AFH is a rare tumor with a high probability of misdiagnosis. Surgeons must be aware of the presence of AFH and conduct a careful follow-up.

Primary Undifferentiated Pleomorphic Sarcoma of the Biceps Femoris Muscle Complicated by Hemorrhage: An Underrecognized Entity

Malignant fibrous histiocytoma currently known as undifferentiated pleomorphic sarcoma is the commonest soft tissue sarcoma of mesenchymal origin. Undifferentiated pleomorphic sarcoma is commonly located in the extremities, trunk, head and neck in decreasing order of frequency. We report a case of primary undifferentiated pleomorphic sarcoma of the biceps femoris muscle in a 50-year-old male complicated by hemorrhage. Diagnostic workup included ultrasonography, magnetic resonance imaging (MRI), histopathology and positive results on immunohistochemistry especially CD-68. High-grade liposarcoma and rhabdomyosarcoma were regarded as differential diagnoses of undifferentiated pleomorphic sarcoma. Demonstration of spontaneous hemorrhage within the lesion on follow-up ultrasonography done at one month from the time of diagnosis deserves a special mention in this report. Radical excision with tumor-free margins of the biceps femoris and tendon reconstruction was undertaken. MRI at six months follow-up did not reveal tumor recurrence at the site of surgery and CT chest did not reveal metastases.

Angiomatoid Fibrous Histiocytoma: A Series of Three Cases

Angiomatoid fibrous histiocytoma (AFH) is a rare, slow-growing soft tissue tumor with an intermediate biologic potential and uncertain line of differentiation, and minimal metastatic potential. AFH may mimic both the clinical, histological, and radiological findings of several tumors; therefore, it is frequently misdiagnosed. 

Three cases of AFH were included in this study. A six-year-old male and two females with an age of 12 and 17 years are presented. The primary locations were in the right shoulder (case 1), left medial proximal thigh (case 2), and left lateral knee (case 3). Two cases (cases 2&3) were presented with a painful mass. In the three patients, the masses were firm, mobile, and not attached to the skin. 

Magnetic resonance imaging (MRI) was done, illustrating unspecific findings to reach a diagnosis. Needle biopsies were performed in all patient, and the diagnosis of AFH was reached. All three patients underwent wide surgical excision of the tumor. Patients were followed up routinely every three to four months with imaging studies to rule out recurrence and metastasis, for a period of 15 months (case 1), 26 months (case 2), and 19 months (case 3), which all resulted negatively. 

SOX9 Immunohistochemistry in the Distinction of Angiomatoid Fibrous Histiocytoma From Histologic Mimics: Diagnostic Utility and Pitfalls

Angiomatoid fibrous histiocytoma (AFH) can be diagnostically difficult because of its varied histologic appearance and potential to occur at unusual sites. The identification of recurrent rearrangements (EWSR1-CREB1, EWSR1-ATF1, and FUS-ATF1) is a helpful diagnostic tool. Additional immunohistochemical markers in AFH could aid in restricting the differential diagnosis and selecting appropriate cases for targeted molecular studies. SOX9 is a transcription factor that is crucial for chondrogenesis and is expressed in neoplasms with chondroid differentiation, and other malignant bone and soft tissue tumors. Recently a role of EWS in regulation of SOX9 expression has been reported, the rearrangements typical of AFH may play a role in SOX9 expression. In this study, we analyzed SOX9 expression in 13 pediatric AFH with varying histology, and an additional 80 cases of other myofibroblastic or fibrohistiocytic lesions. SOX9 expression was present in 11 of 13 AFH, 2 of 53 dermatofibroma (1 aneurysmal and 1 cellular) and 1 calcifying aponeurotic fibroma. The remaining tumors were negative. SOX9 is selectively expressed in AFH and may be a useful maker in combination with desmin, CD99, CD68, and EMA in small biopsies, especially in cases with unusual morphologic features. SOX9 appears to be highly specific for AFH, being weakly expressed in a subset of aneurysmal dermatofibroma and absent in other myofibroblastic lesions, except calcifying aponeurotic fibroma. It should be used with caution when differentiating AFH from malignant neoplasms such as Ewing sarcoma.

Angiomatoid Fibrous Histiocytoma With ALK Expression in an Unusual Location and Age Group

Angiomatoid fibrous histiocytoma (AFH) is a relatively rare soft tissue tumor of intermediate malignant potential, occurring most commonly in young adults, with a recognized propensity for local recurrence and occasional metastasis. A case of AFH occurring on the finger of a 60-year-old man is described in which the unusual location and age group for this entity raised the original wrong diagnosis of an aneurysmal and cellular fibrous histiocytoma. Further workup demonstrated an EWSR1-CREB1 translocation, confirming the correct diagnosis of AFH. Strong anaplastic lymphoma kinase (ALK) expression using the antibody clone D5F3 was demonstrated in our case on immunohistochemistry, which is in concordance with recent findings of anaplastic lymphoma kinase positivity with this antibody in the majority of AFHs.

Intracranial non-myxoid angiomatoid fibrous histiocytoma with EWSR1-CREB1 transcript fusion treated with doxorubicin: A case report

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor that has only been reported in the central nervous system in case reports. After surgery, patients exhibit tumor recurrence. Pathological diagnosis of AHF remains difficult, especially in sites other than skin. AFH can harbor characteristic translocations implying that the Ewing sarcoma breakpoint region 1 gene (EWSR1) fuses with the transcription factor cyclic AMP response element binding (CREB) family genes. Doxorubicin is a chemotherapy that has previously been used successfully in two metastatic soft tissue AFH cases but never in intracranial AFH. The present report describes a case of an adult with a progressive classical intracranial non-myxoid AFH with ESWR1-CREB1 transcript fusion 4 years after surgery. The patient was treated with doxorubicin as a single agent chemotherapy. This treatment resulted in a prolonged stable disease 15 months after treatment discontinuation. This is the first reported case of a treatment with doxorubicin in an adult with progressive intracranial AFH with ESWR1-CREB1 transcript fusion which was sustained after treatment discontinuation.

Tocilizumab Controls Paraneoplastic Inflammatory Syndrome but Does Not Suppress Tumor Growth of Angiomatoid Fibrous Histiocytoma

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor that rarely metastasizes but lacks effective systemic therapy once it propagates. In some reports, high interleukin-6 (IL-6) production promotes tumor growth by autocrine stimulation and tocilizumab, an IL-6 receptor antagonist, can control AFH growth. Here, we present a case report on a patient with local recurrence and distant lymph node metastasis of AFH treated with tocilizumab. As a result, the inhibition of the IL-6 signaling pathway controlled paraneoplastic inflammatory syndrome (PIS); however, the local recurrent tumor progressed. This case implied that IL-6 is not necessarily the cause of tumor growth in AFH. Therefore, physicians should bear in mind that watchful observation is needed whether tocilizumab can control tumor progression despite the amelioration of PIS associated with the attenuated effect of IL-6 on AFH.

Cytokeratin-positive Malignant Tumor in the Abdomen With EWSR1/FUS-CREB Fusion: A Clinicopathologic Study of 8 Cases

ATF1, CREB1, and CREM, which encode the CREB family of transcription factors, are fused with EWSR1 or FUS in human neoplasms, such as angiomatoid fibrous histiocytoma. EWSR1/FUS-CREB fusions have recently been reported in a group of malignant epithelioid tumors with a predilection to the peritoneal cavity and frequent cytokeratin expression. Here, we studied 8 cytokeratin-positive abdominal malignancies with these fusions for further characterization. The tumors affected males (15 to 76 y old) and presented as intra-abdominal masses with concurrent or subsequent peritoneal dissemination, ascites, and/or metastases to the liver or lymph nodes. Four patients died of the disease within 18 to 140 months. Cases 1 to 5 showed multinodular growth of monomorphic epithelioid cells with focal serous cysts. Lymphoplasmacytic infiltration was prominent and was associated with systemic inflammatory symptoms. Two patients suffered from membranous nephropathy with nephrosis. The tumors displayed partly overlapping phenotypes with malignant mesothelioma, including diffuse strong expression of AE1/AE3 and WT1 and membranous positivity of sialylated HEG1, although calretinin was negative. Case 6 showed similar histology to cases 1 to 5, but expressed smooth muscle actin diffusely, lacked WT1 and HEG1, and harbored prominent pseudoangiomatous spaces. Cases 7 and 8 displayed dense growth of small oval to short spindle cells, with occasional molding and minor swirling, superficially resembling small cell carcinoma. Lymphoplasmacytic infiltration was not observed. The tumors were positive for AE1/AE3 and CD34 (focal), whereas calretinin, WT1, and HEG1 were negative. The detected fusions were FUS-CREM (n=4), EWSR1-ATF1 (n=2), EWSR1-CREB1 (n=1), and EWSR1-CREM (n=1). We confirmed the prior observation that these tumors do not fit perfectly with known entities and provided additional novel clinicopathologic information. The tumors require wider recognition because of more aggressive behavior than angiomatoid fibrous histiocytoma despite similar genetics, and potential misdiagnosis as unrelated diseases, such as neuroendocrine neoplasms.

Distinct clinicopathological features of pulmonary primary angiomatoid fibrous histiocytoma: A report of four new cases and review of the literature

BACKGROUND

The aim of this study was to highlight the clinicopathological features of pulmonary primary angiomatoid fibrous histiocytoma (PPAFH) to assist with a differential diagnosis.

METHODS

There were 10 previous reports in the literature and four new PPAFH cases reviewed in this study. Immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) and DNA and RNA-based next-generation sequencing (NGS) was performed in the four new cases reported here.

RESULTS

In the four new PPAFH cases, the ages of occurrence were in patients age from 33 to 55 years and tumor sizes were from 1.5 to 8 cm. Three of four (75.0%) tumors were located in the endobronchus. The most common morphological changes included delineated fibrous capsule (100%, 4/4), lymphoplasmacytic cuff (100%, 4/4), and dense or richly lymphoplasmatic infiltration (100%, 4/4). IHC analysis revealed that the tumor cells of four cases expressed vimentin and TLE1, ALK and CD163 or CD68 was positive in three cases, epithelial membrane antigen (EMA), desmin was positive in two cases, and SMA focal positive expression was observed in two cases. EWSR1 gene rearrangement was positive in all PPAFH cases (100%, 4/4) by FISH detections and four cases were confirmed as EWSR1-CREB1 fusion variant by DNA and RNA based NGS. No regional lymph nodes and distal metastasis, recurrences and death of disease after surgical excision were recorded in all four cases.

CONCLUSIONS

PPAFH is a very unusual pulmonary primary mesenchymal tumor and the clinicopathological features are like other unusual sites counterparts, but with a smaller tumor size, related with large airway, with a tendency to exhibit benign biological behavior, with EWSR1 gene rearrangement and higher frequency of EWSR1-CREB1 gene fusion.

KEY POINTS

Significant findings in the study: In comparison with "classic somatic" and nonpulmonary visceral angiomatoid fibrous histiocytoma, pulmonary primary angiomatoid fibrous histiocytoma display distinct clinicopathological features and prognosis. What this study adds The study provided the pathological differential diagnostic criteria and clinico-pathological features for pulmonary primary angiomatoid fibrous histiocytoma.

PD-L1 expression in angiomatoid fibrous histiocytoma

Angiomatoid fibrous histiocytoma (AFH) is a rare tumor of intermediate malignancy. Treatment options for unresectable and/or metastatic tumors are very limited. Immunotherapy with PD-1/PD-L1 inhibitors may be worth exploring. The aim of this study was to evaluate the expression of PD-L1 in AFHs. PD-L1 expression was assessed on 36 AFHs from 36 pediatric patients by immunohistochemical staining of PD-L1 (clone 22C3). Positivity was defined as membranous expression in ≥ 1% of either tumor or immune cells. The correlations between PD-L1 expression and clinicopathologic features were assessed. Two patients had lymph node metastasis. All patients underwent surgical resection; three of them also had systemic chemotherapy. Three patients had recurrence after initial resection; all patients were alive with a median follow-up of 2.5 years. Overall, twenty-two (61%) tumors were positively stained for PD-L1 and positivity was seen on both tumor and immune cells in eighteen of the 22 tumors. A positive correlation was found between tumor cell PD-L1 expression and CD8+ T-cell infiltration. There were no statistically significant differences between the status of PD-L1 expression and the clinicopathological features assessed. PD-L1 expression was identified in 61% of AFHs with a predominantly adaptive pattern. Our findings provide a rationale for future studies evaluating the potential of checkpoint immunotherapy for patients with unresectable and/or metastatic tumor.

Angiomatoid fibrous histiocytoma (AFH) unusual clinical presentation and unique radiological findings

Angiomatoid fibrous histiocytoma (AFH) are rare soft tissue mesenchymal neoplasms that commonly affect children and young adults. They are classified as “intermediate tumours of uncertain differentiation”. We present a case of an 8-year-old child with a left thigh AFH and antecedent history of minor trauma showing perilesional oedema and enhancement at MRI, leading to an initial working diagnosis of infected haematoma that contributed to the challenge in reaching the final diagnosis. Although most of the imaging features of AFH previously described in the literature are demonstrated in this case, the presence of arterial vascular channels within the tumour and feeding branch from the left profunda femoris artery is unusual and to our knowledge the first to be published in the literature.

Cranial angiomatoid fibrous histiocytoma: A case report and review of literature

Background:

Angiomatoid fibrous histiocytoma (AFH) is a rare low-grade soft-tissue tumor that typically arises from the deep dermal and subcutaneous tissue of the extremities in children and young adults. Intracranial AFH is exceedingly rare, and only four cases of primary AFH tumors have been reported to date.

Case Description:

A 43-year-old male presented to our hospital with headaches, vision changes, and a known brain tumor suspected to be an atypical meningioma. After undergoing craniotomy for resection of the mass, the immunomorphologic features of the resected tumor showed typical features of AFH with ESWR1 (exon7) – ATF1 (exon 5) fusion.

Conclusion:

AFH is a difficult tumor to diagnose with imaging and histologic studies. Thus, further knowledge is necessary – particularly of intracranial cases – to aid clinicians in its diagnosis and management.

Metastatic aneurysmal fibrous histiocytoma in a 20-year-old woman: A rare case report with review of the literature and discussion of its genomic features

Aneurysmal fibrous histiocytoma is an uncommon variant of cutaneous fibrous histiocytomas with a local recurrence rate of 19%. We present a case of aneurysmal fibrous histiocytoma in a 20-year-old female with a regional lymph node metastasis and subsequent satellite nodule. The patient initially presented with a 1-month history of two palpable nodules in left lower anterior shoulder and left axilla. Needle core biopsies from both lesions revealed an atypical spindle cell neoplasm with a differential diagnosis of aneurysmal fibrous histiocytoma and angiomatoid fibrous histiocytoma. The axillary dissection confirmed a metastatic deposit in 1 out of 22 lymph nodes. At 6 months a satellite nodule arose between the resection scar and the axilla histopathologically demonstrating a cellular spindle cell nodule at the dermis subcutaneous junction with large, blood-filled pseudovascular spaces lined by histiocytes. The periphery of the lesion showed collagen trapping without a lymphoplasmacytic infiltrate. The lesional cells were diffusely positive for CD10 and focally for CD68 and Illumina RNA fusion panel sequencing was negative. Herein we present this case of metastatic aneurysmal fibrous histiocytoma with review of the literature and discussion of biology, cytogenetic alterations, and differential diagnosis.

A scoping review and proposed workflow for multi-omic rare disease research

BACKGROUND

Patients with rare diseases face unique challenges in obtaining a diagnosis, appropriate medical care and access to support services. Whole genome and exome sequencing have increased identification of causal variants compared to single gene testing alone, with diagnostic rates of approximately 50% for inherited diseases, however integrated multi-omic analysis may further increase diagnostic yield. Additionally, multi-omic analysis can aid the explanation of genotypic and phenotypic heterogeneity, which may not be evident from single omic analyses.

MAIN BODY

This scoping review took a systematic approach to comprehensively search the electronic databases MEDLINE, EMBASE, PubMed, Web of Science, Scopus, Google Scholar, and the grey literature databases OpenGrey / GreyLit for journal articles pertaining to multi-omics and rare disease, written in English and published prior to the 30th December 2018. Additionally, The Cancer Genome Atlas publications were searched for relevant studies and forward citation searching / screening of reference lists was performed to identify further eligible articles. Following title, abstract and full text screening, 66 articles were found to be eligible for inclusion in this review. Of these 42 (64%) were studies of multi-omics and rare cancer, two (3%) were studies of multi-omics and a pre-cancerous condition, and 22 (33.3%) were studies of non-cancerous rare diseases. The average age of participants (where known) across studies was 39.4 years. There has been a significant increase in the number of multi-omic studies in recent years, with 66.7% of included studies conducted since 2016 and 33% since 2018. Fourteen combinations of multi-omic analyses for rare disease research were returned spanning genomics, epigenomics, transcriptomics, proteomics, phenomics and metabolomics.

CONCLUSIONS

This scoping review emphasises the value of multi-omic analysis for rare disease research in several ways compared to single omic analysis, ranging from the provision of a diagnosis, identification of prognostic biomarkers, distinct molecular subtypes (particularly for rare cancers), and identification of novel therapeutic targets. Moving forward there is a critical need for collaboration of multi-omic rare disease studies to increase the potential to generate robust outcomes and development of standardised biorepository collection and reporting structures for multi-omic studies.

Small soft tissue masses indeterminate at imaging: histological diagnoses at a tertiary orthopedic oncology clinic

OBJECTIVE

To review histologic diagnoses of soft-tissue masses (STMs) ≤ 2 cm with indeterminate imaging features encountered in musculoskeletal oncology clinic at a tertiary referral center.

MATERIALS AND METHODS

This was an IRB-approved retrospective review of patients with STMs ≤ 2 cm, referred to our tertiary care orthopedic oncology clinic over 4.75 consecutive years. Maximum diameter was based on imaging measurement by a fellowship-trained musculoskeletal radiologist. Simple lipomas, synovial cysts, metastases, and cases without histologic confirmation were excluded. Patient demographics, tumor imaging features (location, depth, size, and tumor:muscle enhancement and T2 signal ratios), and histology were recorded and compared.

RESULTS

Mean maximum diameter for 42 trunk/extremity STMs was 1.5 cm (range, 0.7 to 2 cm). Mean age was 48 years (range, 18-83 years). Nine (21%) of the masses were malignant, while 33 (79%) were non-malignant. Thirty-nine (93%) of masses were superficial; 7/39 (18%) of these superficial tumors were malignant. Malignancy was not associated with underlying vessels, tendon, or fascia (p = 0.19). The non-malignant vs. malignant tumor:muscle enhancement ratio was 2.15 vs. 2.32 (p = 0.58) and enhancement coefficient of variation was 0.14 vs. 0.10 (p = 0.29). Most common malignant histologic subtypes were synovial sarcoma (n = 3), fibroblastic/myofibroblastic sarcoma (n = 2), leiomyosarcoma (n = 2), myxofibrosarcoma (n = 1), and angiomatoid fibrous histiocytoma (n = 1). The majority (67%) of non-malignant lesions were: leiomyoma (n = 6), angiomyoma (n = 5), schwannoma (n = 4), benign fibrous histiocytoma (n = 4), and hemangioma (n = 3).

CONCLUSIONS

At a tertiary musculoskeletal oncology referral clinic, primary STMs ≤ 2 cm with indeterminate imaging features should be managed cautiously despite their small size and/or superficial location.

Difficult diagnosis of Angiomatoid Fibrous Histiocytoma of the leg mimicking a benign condition

Angiomatoid fibrous histiocytoma is a rarely metastasizing soft-tissue tumor of low-grade malignancy. Here we report a case of angiomatoid fibrous histiocytoma located in the leg of a 15-year-old female. This case is of particular interest due to its radiological features that led to raise two questions concerning the nature of the disease (is it reactive or tumoral?) and its site of origin (within soft tissues or the tibial periosteum?). Here we describe ultrasound, magnetic resonance imaging, computed tomography scan and positron emission tomography findings that helped answer these questions, understand the real nature of the disease and its appropriate treatment. This case shows that a single type of imaging technique may not be sufficient to understand the real nature of a musculoskeletal lesion and that it is necessary to combine all information derived from various imaging techniques in order to correctly diagnose and treat the disease.

Vascular anomaly imaging mimics and differential diagnoses

Vascular anomalies can be correctly diagnosed in the majority of instances using the combination of clinical history, physical examination and imaging. In certain cases, the clinical work-up may be inconclusive or unavailable to the radiologist, and the imaging findings can be nonspecific, yielding more than one possible diagnosis. In this pictorial essay, we discuss diagnoses that can mimic vascular anomalies and highlight key differentiating imaging features.

Treatment of angiomatoid fibrous histiocytoma after unplanned excision: a case report

Background

Angiomatoid fibrous histiocytoma (AFH) is a relatively uncommon soft tissue tumor of intermediate biologic potential. It occurs in subcutaneous regions of the extremities or the trunk, usually presenting in children or young adults. This is the first reported case of subcutaneous AFH that developed in the iliac region and was treated with an unplanned resection.

Case presentation

An 11-year-old girl noticed a small subcutaneous nodule in the iliac region. As the nodule was asymptomatic, it was observed naturally for a year, after which her parents consulted her doctor due to gradual growth of the nodule. The tumor was resected marginally without biopsy by a non-specialized surgeon. Based on the histology of the resected specimen, the tumor was suspected to be a sarcoma. The patient was referred to our hospital where we reinvestigated the histology of the tumor using immunohistochemistry. After confirming diagnosis of the tumor as an AFH, we undertook additional extensive resection in the iliac region where the tumor had developed. There was no evidence of tumor residue in the resected specimen. It has been 3 years since the operation, and there has been no evidence of recurrence.

Conclusion

We treated a case of AFH after unplanned resection. If subcutaneous tumors in the iliac region are detected, a diagnosis of AFH should be considered and a simple resection avoided.