Frequency and characterization of HMGA2 and HMGA1 rearrangements in mesenchymal tumors of the lower genital tract

Aggressive angiomyxoma of female pelvis and perineum: Retrospective study of 17 cases

OBJECTIVE

Aggressive angiomyxoma is an uncommon mesenchymal neoplasm characterized by a high recurrence rate, usually observed in the lower genital tract of women during their reproductive age.

STUDY DESIGN

Seventeen cases of aggressive angiomyxoma confirmed by pathology from January 2007 to December 2021 in Beijing Chao-yang Hospital were included. We collected clinical data and summarized the clinical and immunohistochemical features.

RESULTS

All seventeen included patients were females, aged between 23 and 57 years (mean, 37.7 years; median, 42 years). Fourteen patients were newly diagnosed and three were recurrent. The tumors were located in vulva (58.8 %), vagina (23.5 %), buttock (11.8 %), and cervix (5.9 %). The tumors size were 2 to 15 cm in greatest dimension (mean 8 ± 4.4 cm, median 6 cm). Follow-up data was available for nine patients, which ranged from 25 to 124 months (mean, 82 months; median, 80 months). At the end of follow-up, no other recurrence or metastasis was reported. Immunohistochemical analysis showed immunoreactive for estrogen (10/11) and progesterone (8/11) receptor, desmin (6/8), smooth muscle actin (4/10), and vimentin (4/4), S-100 (1/8) and CD34 (1/7). The Ki67 level was less than 5 % in five cases.

CONCLUSIONS

AAM is a hormone-sensitive, distinct rare mesenchymal neoplasm with high incidence of local recurrence. Surgery is the preferred treatment, with complete resection being an essential prerequisite for minimizing the risk of recurrence.

Aggressive Angiomyxoma of the Lower Female Genital Tract in Pregnancy: A Review of the MITO Rare Tumors Group

Deep (aggressive) angiomyxoma of the lower genital tract is a rare malignancy affecting women of reproductive age. Being a hormone-sensitive tumor, its growth is particularly benefitted during pregnancy. Surgical excision with complete resection is indicated, even if a wait-and-see approach can be considered until delivery, to avoid destructive surgeries. The mode of delivery is to be evaluated based on the location and size of the neoplasm; vaginal delivery is not contraindicated, as long as the tumor does not obstruct the birth canal. Positive surgical margins are the most important prognostic factor for recurrence. Adjuvant therapy with gonadotropin-releasing hormone analogues may be proposed after pregnancy, in the case of non-radical surgery. Despite the high local relapse rate, the outcomes for mother and child are favorable. Since recurrences can occur after many years, the patient should be included in long-term follow-up.

Vulvar angiomyofibroblastoma is molecularly defined by recurrent MTG1-CYP2E1 fusions

Angiomyofibroblastoma (AMF), a rare benign vulvovaginal mesenchymal tumour, poses a diagnostic challenge due to histologic and immunohistochemical overlap with other vulvar mesenchymal tumours. Recently, MTG1-CYP2E1 fusion transcripts were reported in 5/5 AMFs; no other genetic alterations have been described to date. Herein, we sought to investigate the frequency of the MTG1-CYP2E1 fusion and the presence of other potential genetic alterations in a cohort of AMFs (n = 7, patient age range: 28-49 years). Tumours demonstrated classic morphologic features including alternating hypo/hypercellular areas, capillary channels surrounded by epithelioid/spindled tumour cells, and variable amounts of mature adipose tissue. reverse transcription-polymerase chain reaction (RT-PCR) for MTG1-CYP2E1 fusion, performed in all seven cases, showed the fusion transcript in five of six cases (one case with technical failure). Two tumours, including the one lacking the fusion, were subjected to targeted next-generation sequencing (104 genes) and a sarcoma fusion assay (28 genes); the fusion negative AMF also underwent RNA sequencing. No additional mutations, copy number alterations, or fusion genes were identified with the assays employed. We conclude that the majority of AMFs harbour recurrent MTG1-CYP2E1 fusion transcripts and identification of this fusion may aid in the diagnosis.

Aggressive angiomyxoma of pelvis: A case report and literature review

RATIONALE

Aggressive angiomyxoma (AAM) is a rare mesenchymal tumor primarily involving the lower genital tract of reproductive females. It often shares pathologic morphology with other mesenchymal lesions, which result in diagnostic difficulties for pathologists.

PATIENT CONCERNS AND DIAGNOSES

We described the case of a 32-year-old female presenting with a pelvic mass. Imaging examination showed a "swirling sign" within the mass. The mass was 10.2 × 10 × 7.7 cm, located in the right front of the uterus, with unclear demarcation from the surrounding organs and tissues. The gross appearance was grayish brown with a solid section and a myxedematous cut surface. Microscopically, it was a mesenchymal tumor with a presence of perivascular smooth muscle fibers radiating from the blood vessel and an infiltrative growth pattern. The pelvic AAM was diagnosed based on clinicopathologic and imaging features.

INTERVENTIONS AND OUTCOMES

A surgery with local excision of the mass was performed. The patient experienced 1 relapse during 2-year follow-up and underwent the radiation therapy.

LESSONS

When the pathological morphology of AAM overlaps with other mesenchymal lesions, the comprehensive understanding of tumor clinicopathological characteristics combined with imaging features is important for the accurate diagnosis of AAM.

Update on Mesenchymal Lesions of the Lower Female Genital Tract

This article provides an update of the recent developments in mesenchymal tumors of lower genital tract. We focus on the characterization of recurrent molecular events in certain genital stromal tumors, for instance angiomyofibroblastomas and superficial myofibroblastomas. Moreover, fusions involving Tyrosine-kinases receptors (NTRK, FRFR1, RET, COL1A1-PDGFB) have been demonstrated in an emerging group of mesenchymal tumors characterized by a fibrosarcoma-like morphology and a predilection for uterine cervix of premenopausal women. We also cover the topic of smooth muscle tumors of the lower genital tract, which can be now classified using the same diagnostic criteria than their uterine counterpart..

Angiomyofibroblastoma and Potential Mimicking Soft Tissue Tumors That May Occasionally Present in the Retroperitoneum: An Approach to the Differential Diagnosis With Report of an Unusual Index Case Abutting the Kidney

The retroperitoneal soft tissues, extending from the pelvic floor to the level of the diaphragm, are the source of a variety of mesenchymal neoplasms with overlapping features and distinct clinical behaviors, making their distinction of crucial importance. Herein, we report a rare retroperitoneal angiomyofibroblastoma (AMFB) that presented as a right abdominal mass in a 25-year-old woman and that clinically simulated a primary renal carcinoma. The patient underwent complete surgical resection showing a well-circumscribed tumor adjacent to but separate from the right kidney. It was comprised of irregular, often anastomosing islands and cords of plump to spindled cells in a collagenous stroma with numerous thin-walled vessels. The tumor cells clustered around the vessels and admixed with moderate numbers of adipocytes. There was neither significant nuclear atypia nor mitotic activity. Immunohistochemically, the tumor cells showed strong reactivity for desmin, diffuse expression of estrogen and progesterone receptors, retained nuclear expression of retinoblastoma protein, and absent CD34 expression. The immunomorphological features were these of a "lipomatous variant" of AMFB of the retroperitoneum. The occurrence of AMFB in the retroperitoneum is unexpected since it mostly develops in the lower genital tract of young women, making its recognition in this rare location difficult. As a consequence, more common pelvic or retroperitoneal soft tissue neoplasms may represent the primary diagnostic considerations. We, therefore, review a variety of soft tissue tumors occurring in the pelvis/retroperitoneum that, to some degree, may mimic AMFB, and present key findings to assist in accurate diagnosis.

Practical Approach to the Diagnosis of the Vulvo-Vaginal Stromal Tumors: An Overview

Background: The category of the “stromal tumors of the lower female genital tract” encompasses a wide spectrum of lesions with variable heterogeneity, which can be nosologically classified on the basis of their morphologic and immunohistochemical profiles as deep (aggressive) angiomyxoma (DAM), cellular angiofibroma (CAF), angiomyofibroblastoma (AMFB) or myofibroblastoma (MFB). Despite the differential diagnosis between these entities being usually straightforward, their increasingly recognized unusual morphological variants, along with the overlapping morphological and immunohistochemical features among these tumours, may raise serious differential diagnostic problems. Methods and Results: The data presented in the present paper have been retrieved from the entire published literature on the PubMed website about DAM, CAF, AFMB and MFB from 1984 to 2021. The selected articles are mainly represented by small-series, and, more rarely, single-case reports with unusual clinicopathologic features. The present review focuses on the diagnostic clues of the stromal tumours of the lower female genital tract to achieve a correct classification. The main clinicopathologic features of each single entity, emphasizing their differential diagnostic clues, are discussed and summarized in tables. Representative illustrations, including the unusual morphological variants, of each single tumour are also provided. Conclusion: Awareness by pathologists of the wide morphological and immunohistochemical spectrum exhibited by these tumours is crucial to achieve correct diagnoses and to avoid confusion with reactive conditions or other benign or malignant entities.

Potential pathogenetic link between angiomyofibroblastoma and superficial myofibroblastoma in the female lower genital tract based on a novel MTG1-CYP2E1 fusion

Angiomyofibroblastoma and superficial myofibroblastoma are distinctive benign mesenchymal tumors occurring in the female lower genital tract. Despite their significant overlapping clinicopathologic features, including the presence of bland-looking spindle or oval cells with myofibroblastic or myoid differentiation, the tumors have been regarded as separate entities. Although subepithelial, hormone-sensitive mesenchymal cells of the female lower genital tract are considered as their potential common progenitor cells, their potential kinship or pathogenetic similarities remain elusive. Based on the identification of a novel RNA sequencing-based MTG1-CYP2E1 fusion transcript in an angiomyofibroblastoma index case, we investigated an additional ten samples of the tumor and its site-specific histological mimics, including eight superficial myofibroblastomas, four deep angiomyxomas, four cellular angiofibromas, three fibroepithelial stromal polyps, and eight non-site-specific mesenchymal tumors occurring in the female lower genital tract. Using reverse transcription-polymerase chain reaction, we showed that the MTG1-CYP2E1 fusion transcripts were consistently detectable in angiomyofibroblastomas (5/5, 100%) and often in superficial myofibroblastomas (3/5, 60%) but were not detected in the other examined site-specific or non-site-specific mesenchymal tumors. Our immunohistochemical experiments showed that CYP2E1, an isoenzyme belonging to the cytochrome P450 superfamily, exhibited increased positivity in tumors with MTG1-CYP2E1 than was observed in fusion-negative tumors (RR = 6.56, p = 0.001). The results of our study provide further evidence supporting the assertion that angiomyofibroblastoma and superficial myofibroblastoma represent phenotypic variants of site-specific mesenchymal tumors and share a common oncogenic mechanism.

HMGA2 Is a Useful Marker of Vulvovaginal Aggressive Angiomyxoma But May Be Positive in Other Mesenchymal Lesions at This Site

Aggressive angiomyxoma (AA) is a rare mesenchymal neoplasm occurring almost exclusively in the vulvovaginal region and which has a wide differential diagnosis. It has previously been suggested that the nuclear transcription factor HMGA2 is a useful marker of AA, although the number of studies is limited. We investigated HMGA2 immunoreactivity in a large series (n=284) of vulvovaginal mesenchymal lesions. HMGA2 nuclear staining was classified as diffuse (≥50%), focal (<50%), or negative. Of 38 cases of AA, 26 (68%) were positive; 77% (n=20) of these exhibited diffuse staining. Of the 41 smooth muscle tumors, 18 (44%) were positive with 16 (89%) exhibiting diffuse staining. 80 fibroepithelial stromal polyps were included and 15 (19%) were positive (8 diffuse; 7 focal). Most of the fibroepithelial stromal polyps that exhibited diffuse HMGA2 immunoreactivity were large and edematous. Occasional cases of a variety of other lesions were positive, including 1 of 30 superficial myofibroblastomas and 1 of 16 angiomyofibroblastomas. Cellular angiofibromas (n=12) and superficial angiomyxomas (n=6) were always negative. Our results confirm that HMGA2 is a useful marker of AA but a significant minority of cases are negative. The marker also lacks specificity, since a high percentage of smooth muscle tumors are positive, although these typically do not bear a close morphologic resemblance to AA. A novel observation in our study is positive staining of some fibroepithelial stromal polyps, particularly when large and edematous; these are particularly likely to be confused morphologically with AA and positive staining with HMGA2 represents a significant diagnostic pitfall.

Vascular biology of uterine fibroids: connecting fibroids and vascular disorders

Fibroids are benign tumors caused by the proliferation of myometrial smooth muscle cells in the uterus that can lead to symptoms such as abdominal pain, constipation, urinary retention, and infertility. While traditionally thought of as a disease process intrinsic to the uterus, accumulating evidence suggests that fibroid growth may be linked with the systemic vasculature system, although cell-intrinsic factors are certainly of principal importance in their inception. Fibroids are associated with essential hypertension and preeclampsia, as well as atherosclerosis, for reasons that are becoming increasingly elucidated. Factors such as the renin-angiotensin-aldosterone system, estrogen, and endothelial dysfunction all likely play a role in fibroid pathogenesis. In this review, we lay out a framework for reconceptualizing fibroids as a systemic vascular disorder, and discuss how pharmaceutical agents and other interventions targeting the vasculature may aid in the novel treatment of fibroids.

3' UTR-truncated HMGA2 overexpression induces non-malignant in vivo expansion of hematopoietic stem cells in non-human primates

Vector-mediated mutagenesis remains a major safety concern for many gene therapy clinical protocols. Indeed, lentiviral-based gene therapy treatments of hematologic disease can result in oligoclonal blood reconstitution in the transduced cell graft. Specifically, clonal expansion of hematopoietic stem cells (HSCs) highly expressing HMGA2, a chromatin architectural factor found in many human cancers, is reported in patients undergoing gene therapy for hematologic diseases, raising concerns about the safety of these integrations. Here, we show for the first time in vivo multilineage and multiclonal expansion of non-human primate HSCs expressing a 3' UTR-truncated version of HMGA2 without evidence of any hematologic malignancy >7 years post-transplantation, which is significantly longer than most non-human gene therapy pre-clinical studies. This expansion is accompanied by an increase in HSC survival, cell cycle activation of downstream progenitors, and changes in gene expression led by the upregulation of IGF2BP2, a mRNA binding regulator of survival and proliferation. Thus, we conclude that prolonged ectopic expression of HMGA2 in hematopoietic progenitors is not sufficient to drive hematologic malignancy and is not an acute safety concern in lentiviral-based gene therapy clinical protocols.

Recurrent perineal aggressive angiomyxoma: dilemma in diagnosis and outcome of this rare disease

Aggressive angiomyxoma (AAM) is a very rare, benign, locally infiltrative mesenchymal tumour with a high chance of recurrence following surgical excision. In the male population, it is so rare that less than only 50 cases have been reported so far. We present a case of a large recurrent perineal AAM in a man who presented with swelling in the perineal region following surgical excision 3 years ago. After evaluation, the diagnostic dilemma of a possible perineal hernia or recurrence remained. Surgical exploration ruled out hernia and the tumour was excised with difficulty. Immunohistochemical examination showed tumour cells with diffuse nuclear positivity for oestrogen receptor and patchy cytoplasmic positivity for desmin (A2). Histological and immunohistochemical features confirmed the diagnosis. Being very rare, AAMs need to be considered as a differential diagnosis of pelvic/perineal tumours among males. With no standardised therapy for AAM, complete resection would be the goal of therapy.

Gynecological Sarcomas: Molecular Characteristics, Behavior, and Histology-Driven Therapy

Gynecological sarcomas represent 3% to 4% of all gynecological malignancies and 13% of all sarcomas. The uterus is the most frequent primary site (83%); less frequently sarcomas are diagnosed originating from the ovary (8%), vulva and vagina (5%), and other gynecologic organs (2%). As the classification of gynecologic sarcomas continues to diversify, so does the management. Accurate histopathologic diagnosis, utilizing appropriate ancillary immunohistochemical and molecular analysis, could lead to a more personalized approach. However, there are subtypes that require further definition, with regard to putative predictive markers and optimal management. The aim of this review is to highlight the importance of accurate diagnosis and classification of gynecologic sarcoma subtypes by the surgical pathologist in order to provide more tailored systemic treatment, and to highlight the increasing importance of close collaboration between the pathologist and the oncologist.

Mesenchymal lesions of the vulva

Mesenchymal lesions of the vulva include site-specific entities limited to the lower genital tract, as well as a range of non-site-specific tumors that are more common at extragenital sites. Site-specific lesions include fibroepithelial stromal polyp, cellular angiofibroma, angiomyofibroblastoma, and aggressive angiomyxoma. Non-site-specific tumors that may occur in the vulva include those of smooth muscle, skeletal muscle, vascular, neural, adipocytic, and uncertain differentiation. This review discusses both site-specific and non-site-specific vulvar mesenchymal lesions including non-neoplastic proliferations, benign neoplasms, locally aggressive neoplasms with a predilection for local recurrence, neoplasms of indeterminate biologic potential, and frankly malignant neoplasms with a high risk of distant metastasis and death. Accurate diagnosis is essential for proper management, and is facilitated by correlation with clinical findings and targeted application of immunohistochemical and molecular studies.

High Mobility Group AT-Hook 2 (HMGA2) Oncogenicity in Mesenchymal and Epithelial Neoplasia

High mobility group AT-hook 2 (HMGA2) has been associated with increased cell proliferation and cell cycle dysregulation, leading to the ontogeny of varied tumor types and their metastatic potentials, a frequently used index of disease prognosis. In this review, we deepen our understanding of HMGA2 pathogenicity by exploring the mechanisms by which HMGA2 misexpression and ectopic expression induces mesenchymal and epithelial tumorigenesis respectively and distinguish the pathogenesis of benign from malignant mesenchymal tumors. Importantly, we highlight the regulatory role of let-7 microRNA family of tumor suppressors in determining HMGA2 misexpression events leading to tumor pathogenesis and focused on possible mechanisms by which HMGA2 could propagate lymphangioleiomyomatosis (LAM), benign mesenchymal tumors of the lungs. Lastly, we discuss potential therapeutic strategies for epithelial and mesenchymal tumorigenesis based on targeting the HMGA2 signaling pathway.

Radiomic features from MRI distinguish myxomas from myxofibrosarcomas

BACKGROUND

Myxoid tumors pose diagnostic challenges for radiologists and pathologists. All myxoid tumors can be differentiated from each other using fluorescent in-situ hybridization (FISH) or immunohistochemical markers, except for myxomas and myxofibrosarcomas. Myxomas and myxofibrosarcomas are rare tumors. Myxomas are benign and histologically bland, whereas myxofibrosarcomas are malignant and histologically heterogenous. Because of the histological heterogeneity, low grade myxofibrosarcomas may be mistaken for myxomas on core needle biopsies. We evaluated the performance of T1-weighted signal intensity (T1SI), tumor volume, and radiomic features extracted from magnetic resonance imaging (MRI) to differentiate myxomas from myxofibrosarcomas.

METHODS

The MRIs of 56 patients (29 with myxomas, 27 with myxofibrosarcomas) were analyzed. We extracted 89 radiomic features. Random forests based classifiers using the T1SI, volume features, and radiomic features were used to differentiate myxomas from myxofibrosarcomas. The classifiers were validated using a leave-one-out cross-validation. The performances of the classifiers were then compared.

RESULTS

Myxomas had lower normalized T1SI than myxofibrosaromas (p = 0.006) and the AUC using the T1SI was 0.713. However, the classification model using radiomic features had an AUC of 0.885 (accuracy = 0.839, sensitivity = 0.852, specificity = 0.828), and outperformed the classification models using T1SI (AUC = 0.713) and tumor volume (AUC = 0.838). The classification model using radiomic features was significantly better than the classifier using T1SI values (p = 0.039).

CONCLUSIONS

Myxofibrosarcomas are on average higher in T1-weighted signal intensity than myxomas. Myxofibrosarcomas are larger and have shape differences compared to myxomas. Radiomic features performed best for differentiating myxomas from myxofibrosarcomas compared to T1-weighted signal intensity and tumor volume features.

Malignant Tenosynovial Giant Cell Tumor: The True "Synovial Sarcoma?" A Clinicopathologic, Immunohistochemical, and Molecular Cytogenetic Study of 10 Cases, Supporting Origin from Synoviocytes

We present our experience with ten well-characterized malignant tenosynovial giant cell tumors, including detailed immunohistochemical analysis of all cases and molecular cytogenetic study for CSF1 rearrangement in a subset. Cases occurred in 7 M and 3 F (mean age: 52 years; range: 26-72 years), and involved the ankle/foot (n = 1), finger/toe (n = 3), wrist (n = 1), pelvic region (n = 3), leg (n = 1), and thigh (n = 1). There were eight primary and two secondary malignant tenosynovial giant cell tumors. Histologically, all cases showed definite areas of typical tenosynovial giant cell tumor. The malignant areas varied in appearance. In some cases, isolated malignant-appearing large mononuclear cells with high nuclear grade and mitotic activity were identified within otherwise-typical tenosynovial giant cell tumor, as well as forming larger masses of similar-appearing malignant cells. Occasionally, these nodules of malignant large mononuclear cells showed transition to pleomorphic spindle cell sarcoma, with varying degrees of collagenization and myxoid change. One malignant tenosynovial giant cell tumor was composed of sheets of monotonous large mononuclear cells with high nuclear grade, growing in a hyalinized, osteoid-like matrix, with areas of heterologous osteocartilaginous differentiation. Mitotic activity ranged from 2 to 34 mitoses per 10 HPF (mean 18/10 HPF). Geographic necrosis was observed in four cases. The malignant-appearing large mononuclear cells were consistently positive for clusterin and negative for CD163, CD68, and CD11c. Desmin was positive in a small minority of these cells. Areas in malignant tenosynovial giant cell tumor resembling pleomorphic spindle cell sarcoma or osteo/chondrosarcoma showed loss of clusterin expression. RANKL immunohistochemistry was positive in the large mononuclear cells in eight cases. Two cases showed an unbalanced rearrangement of the CSF1 locus. Follow-up (nine patients; range 0.5-66 months; mean 20 months) showed three patients dead of disease, with three other living patients having lung and lymph node metastases; three patients were disease-free. We conclude that malignant tenosynovial giant cell tumors are highly aggressive sarcomas with significant potential for locally destructive growth, distant metastases, and death from disease. The morphologic and immunohistochemical features of these tumors and the presence of CSF1 rearrangements support origin of malignant tenosynovial giant cell tumor from synoviocytes.

Long-standing aggressive angiomyxoma as a paratesticular mass: A case report and review of literature

Objectives:

Aggressive angiomyxoma is known as a mesenchymal tumor of premenopausal women and it is extremely rare in men.

Methods:

Herein, we report a 66-year-old male with a firm scrotal mass that had gradually enlarged over 20 years.

Results:

Radiological studies revealed 10 x 15 cm mass lesion confined to right scrotum with neither local invasion nor distant metastasis. Inguinal orchiectomy was performed and histopathology showed characteristic features of an aggressive angiomyxoma occupying paratesticular region, which was a challenging diagnosis due to its unexpected occurrence in the male gender.

Conclusion:

Aggressive angiomyxoma is mostly considered as a benign tumor in females despite its propensity for local recurrence. Whether it may show a divergent biological behavior in men is unknown as the reported cases are too few.

Intravenous leiomyomatosis: an unusual intermediate between benign and malignant uterine smooth muscle tumors

Intravenous leiomyomatosis is an unusual smooth muscle neoplasm with quasi-malignant intravascular growth but a histologically banal appearance. Herein, we report expression and molecular cytogenetic analyses of a series of 12 intravenous leiomyomatosis cases to better understand the pathogenesis of intravenous leiomyomatosis. All cases were analyzed for the expression of HMGA2, MDM2, and CDK4 proteins by immunohistochemistry based on our previous finding of der(14)t(12;14)(q14.3;q24) in intravenous leiomyomatosis. Seven of 12 (58%) intravenous leiomyomatosis cases expressed HMGA2, and none expressed MDM2 or CDK4. Colocalization of hybridization signals for probes from the HMGA2 locus (12q14.3) and from 14q24 by interphase fluorescence in situ hybridization (FISH) was detected in a mean of 89.2% of nuclei in HMGA2-positive cases by immunohistochemistry, but in only 12.4% of nuclei in negative cases, indicating an association of HMGA2 expression and this chromosomal rearrangement (P=8.24 × 10(-10)). Four HMGA2-positive cases had greater than two HMGA2 hybridization signals per cell. No cases showed loss of a hybridization signal by interphase FISH for the frequently deleted region of 7q22 in uterine leiomyomata. One intravenous leiomyomatosis case analyzed by array comparative genomic hybridization revealed complex copy number variations. Finally, expression profiling was performed on three intravenous leiomyomatosis cases. Interestingly, hierarchical cluster analysis of the expression profiles revealed segregation of the intravenous leiomyomatosis cases with leiomyosarcoma rather than with myometrium, uterine leiomyoma of the usual histological type, or plexiform leiomyoma. These findings suggest that intravenous leiomyomatosis cases share some molecular cytogenetic characteristics with uterine leiomyoma, and expression profiles similar to that of leiomyosarcoma cases, further supporting their intermediate, quasi-malignant behavior.

Dysregulated protease activated receptor 1 (PAR1) promotes metastatic phenotype in breast cancer through HMGA2

As the majority of patients with basal-like breast carcinoma present with invasive, metastatic disease that do not respond to available therapies, it is essential to identify new therapeutic targets that impact invasion and metastasis. Protease-activated receptor 1 (PAR1), a G-protein coupled receptor has been shown to act as an oncogene, but underlying mechanisms are not well understood. Here, we show that ectopic expression of functionally active PAR1 in MCF-7 cells induced a hormone-refractory, invasive phenotype representative of advanced basal-like breast carcinoma that readily formed metastatic lesions in lungs of mice. PAR1 was found to globally upregulate mesenchymal markers, including vimentin, a direct target of PAR1, and downregulate the epithelial markers including E-cadherin, as well as estrogen receptor. In contrast, non-signaling PAR1 mutant receptor did not lead to an invasive, hormone refractory phenotype. PAR1 expression increased spheroid formation and the level of stemness markers and self-renewal capacity in human breast cancer cells. We identified HMGA2 (high mobility group A2) as an important regulator of PAR1-mediated invasion. Inhibition of PAR1 signaling suppresses HMGA2-driven invasion in breast cancer cells. HMGA2 gene and protein are highly expressed in metastatic breast cancer cells. Overall, our results show that PAR1/HMGA2 pathway may present a novel therapeutic target.

Leiomyoma cutis: a focused review on presentation, management, and association with malignancy

Cutaneous leiomyomas (CLs) are rare, sporadic, or inherited tumors of smooth muscle origin associated with various disorders. Hereditary leiomyomatosis and renal cell cancer (HLRCC) is the primary tumor predisposition syndrome associated with inherited CLs, affecting 180 families worldwide, with significant mortality. CLs are subdivided into piloleiomyomas, genital leiomyomas, and angioleiomyomas based on their smooth muscle of origin, as well as their clinicopathologic features. Piloleiomyomas, derived from arrector pili muscle, are solitary or multiple firm papulonodules located typically on the extremities and trunk; genital leiomyomas, derived from dartoic, vulvar, or mammary smooth muscle, are solitary papulonodules or pedunculated papules located on the scrotum, vulva, or nipple; and angioleiomyomas, which include solid, cavernous, or venous subtypes, are derived from the tunica media of small arteries and veins and typically present on the extremities. Partial/excisional biopsy is required for diagnosing all CLs. Histology shows interlacing fascicles of spindle cells with moderate amounts of eosinophilic cytoplasm and a blunt-ended, elongated nucleus with perinuclear halos. Surgical excision is curative for CLs, with other management options including medical or destructive therapy; active surveillance is advised to monitor HLRCC-associated neoplasms, with pharmacological therapies under active research.

Overexpression of the truncated form of High Mobility Group A proteins (HMGA2) in human myometrial cells induces leiomyoma-like tissue formation

The pathogenesis of uterine leiomyomas, the most common benign tumor in women, is still unknown. This lack of basic knowledge limits the development of novel non-invasive therapies. Our group has previously demonstrated that leiomyoma side population (SP) cells are present in tumor lesions and act like putative tumor-initiating stem cells in human leiomyoma. Moreover, accumulated evidence demonstrates that these benign tumors of mesenchymal origin are characterized by rearrangements of the High Mobility Group A proteins (HMGA). In this work, we tested the hypothesis that leiomyoma development may be due to overexpression of HMGA2 (encoding high mobility group AT-hook2) in myometrial stem cells using in vitro and in vivo approaches. Our work demonstrates that the truncated/short form of HMGA2 induces myometrial cell transformation toward putative tumor-initiating leiomyoma cells and opens up new possibilities to understand the origin of leiomyomas and the development of new therapeutic approaches.

Targeted genomic analysis of Müllerian adenosarcoma

Müllerian adenosarcoma (MA) is a rare mixed mesenchymal tumour of the female genital tract, composed of malignant stroma and benign-appearing epithelium. Sarcomatous overgrowth (SO) is the only established histological variable associated with higher stage and shorter survival. Specific molecular or immunohistochemistry (IHC) tools for the diagnosis of MA are lacking. Our goal was to study genomic mutations and copy number variations (CNVs) in MA to understand better its pathobiology, and develop specific diagnostic and prognostic tools. DNA was extracted from 20 samples of MA from 18 subjects (12 without SO and 6 with SO), including two in which areas of both typical MA histology and SO were independently tested. Samples were analysed using a targeted next-generation sequencing assay interrogating exonic sequences of 275 cancer genes for mutations and CNVs as well as 91 introns across 30 genes for cancer-associated rearrangements. The mean number of mutations in MA with SO (mean 9.7; range 3-14) did not differ significantly from that in MA without SO (mean 9.6; range 5-16). MA with SO had significantly higher mean numbers of gene-level CNVs (24.6) compared to MA without SO (5; p = 0.0002). The most frequent amplification involved MDM2 and CDK4 (5/18; 28%), accompanied by focal CDK4 and MDM2 and diffuse HMGA2 expression using immunohistochemistry. MYBL1 amplification was seen in 4/18 (22%), predominantly in SO. Alterations in PIK3CA/AKT/PTEN pathway members were seen in 13/18 (72%). Notably, TP53 mutations were uncommon, present in only two cases with SO. Three out of 18 (17%) had mutations in ATRX, all associated with SO. No chromosomal rearrangements were identified. We have identified a number of recurrent genomic alterations in MA, including some associated with SO. Although further investigation of these findings is needed, confirmation of one or more may lead to new mechanistic insights and novel markers for this often difficult-to-diagnose tumour.

Recurrent PAX3-MAML3 fusion in biphenotypic sinonasal sarcoma

Biphenotypic sinonasal sarcoma (SNS) is a newly described tumor of the nasal and paranasal areas. Here we report a recurrent chromosomal translocation in SNS, t(2;4)(q35;q31.1), resulting in a PAX3-MAML3 fusion protein that is a potent transcriptional activator of PAX3 response elements. The SNS phenotype is characterized by aberrant expression of genes involved in neuroectodermal and myogenic differentiation, closely simulating the developmental roles of PAX3.

Identification of PPAP2B as a novel recurrent translocation partner gene of HMGA2 in lipomas

Most lipomas are characterized by translocations involving the HMGA2 gene in 12q14.3. These rearrangements lead to the fusion of HMGA2 with an ectopic sequence from the translocation chromosome partner. Only five fusion partners of HMGA2 have been identified in lipomas so far. The identification of novel fusion partners of HMGA2 is important not only for diagnosis in soft tissue tumors but also because these genes might have an oncogenic role in other tumors. We observed that t(1;12)(p32;q14) was the second most frequent translocation in our series of lipomas after t(3;12)(q28;q14.3). We detected overexpression of HMGA2 mRNA and protein in all t(1;12)(p32;q14) lipomas. We used a fluorescence in situ hybridization-based positional cloning strategy to characterize the 1p32 breakpoint. In 11 cases, we identified PPAP2B, a member of the lipid phosphate phosphatases family as the 1p32 target gene. Reverse transcription-polymerase chain reaction analysis followed by nucleotide sequencing of the fusion transcript indicated that HMGA2 3' untranslated region (3'UTR) fused with exon 6 of PPAP2B in one case. In other t(1;12) cases, the breakpoint was extragenic, located in the 3'region flanking PPAP2B 3'UTR. Moreover, in one case showing a t(1;6)(p32;p21) we observed a rearrangement of PPAP2B and HMGA1, which suggests that HMGA1 might also be a fusion partner for PPAP2B. Our results also revealed that adipocytic differentiation of human mesenchymal stem cells derived from adipose tissue was associated with a significant decrease in PPAP2B mRNA expression suggesting that PPAP2B might play a role in adipogenesis.

Adipose and myxoid tumors of childhood and adolescence

Adipose and myxoid tumors in children are an unusual and challenging group of neoplasms that have some unique aspects in contrast to these tumors in adults. Less than 10% of soft tissue neoplasms in the 1st 2 decades of life have an adipose phenotype and most are benign. The most common are various types of lipoma and lipoblastoma. Liposarcoma in young patients is rare and has a distinctive distribution of histologic subtypes, including classic myxoid liposarcoma, and unusual variants, such as pleomorphic-myxoid liposarcoma. Pathologic examination enhanced by adjunct techniques, such as immunohistochemistry and cytogenetic or molecular genetic studies, is useful for classification of difficult cases. Myxoid tumors can overlap with adipose tumors and are included in this review because of the morphologic similarities and importance of diagnostic accuracy. This article reviews the clinicopathologic features of adipose and myxoid tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents and the differential diagnosis.

Fusion of dynactin 1 to anaplastic lymphoma kinase in inflammatory myofibroblastic tumor

Inflammatory myofibroblastic tumor is an uncommon neoplasm that occurs more often in younger patients. Approximately 50% of inflammatory myofibroblastic tumors are characterized by anaplastic lymphoma kinase fusion genes, more commonly TPM3-anaplastic lymphoma kinase and TPM4-anaplastic lymphoma kinase. Herein, we report a novel fusion of dynactin 1 to anaplastic lymphoma kinase in a neck inflammatory myofibroblastic tumor diagnosed in a 7-year-old girl. Histologic evaluation showed a perineurioma-like bland spindle cell neoplasm with positive immunohistochemical staining for anaplastic lymphoma kinase, S-100, and CD34 but negative for epithelial membrane antigen. Standard cytogenetic analysis showed a der(2)t(2;12)(p23;q11). Fluorescence in situ hybridization demonstrated separation of the anaplastic lymphoma kinase locus. 5'-rapid amplification of complementary DNA ends polymerase chain reaction identified an in-frame fusion of dynactin 1 exon 16 on chromosome 2 to anaplastic lymphoma kinase exon 20. Reverse transcription-polymerase chain reaction with specific primers and direct sequencing confirmed the fusion. The structure of the fusion protein retains the cytoskeleton-associated protein-glycine domain and coiled coil domain of dynactin 1 and the receptor tyrosine kinase domain of anaplastic lymphoma kinase. This novel fusion gene is structurally similar to other previously described anaplastic lymphoma kinase fusion genes and may be associated with the unusual morphology and immunophenotype of this tumor.

Value and limitation of immunohistochemical expression of HMGA2 in mesenchymal tumors: about a series of 1052 cases

The high mobility group A (HMGA2) gene encodes a protein that alters chromatin structure and regulates the transcription of many genes; it is implicated in both benign and malignant neoplasias, but its rearrangements are a feature of development of several mesenchymal tumors. Given its implication in these tumors and particularly adipocytic tumors, and the availability of antibodies usable on paraffin-embedded tissues, we evaluated the immunohistochemical expression of this gene in a series of 1052 mesenchymal tumors. The objective was to define the value and limitations of HMGA2 immunohistochemical expression for histotyping, and compare with molecular data reported in the literature. We thus analyzed 880 cases on tissue microarray and 182 cases on whole sections (211 adipocytic tumors, 628 sarcomas, 213 benign mesenchymal tumors, and 10 normal adipose tissues). A nuclear immunostaining was detected in 86% of conventional and intramuscular lipomas, in 86% of well-differentiated liposarcomas and in 67% of dedifferentiated liposarcomas, as opposed to 16% of other benign adipose tumors and to 15% of non-well-differentiated liposarcoma/dedifferentiated liposarcoma sarcomas. Among benign mesenchymal tumors and lesions, it was detected in 90% of nodular fasciitis and in 88% of benign fibrous histiocytomas with respective specificities of 85 and 100%, and in 90% of aggressive angiomyxoma, contrary to other vulvovaginal tumor types, which expressed HMGA2 only rarely. The normal adipose tissue was always negative for HMGA2. Although not specific, immunohistochemical detection of the HMGA2 protein is helpful for the distinction of normal adipose tissue from well-differentiated lesions, particularly on biopsy or on re-excision. It is less sensitive than MDM2/CDK4 for dedifferentiated liposarcomas diagnosis, but it appears more specific to distinguish dedifferentiated liposarcomas from other poorly differentiated sarcomas. Finally, and may be more importantly, HMGA2 is useful for the diagnosis of benign fibrous histiocytoma, nodular fasciitis and vulvovaginal benign mesenchymal tumors.

Fusion of HMGA2 to COG5 in uterine leiomyoma

Uterine leiomyomas are smooth muscle tumors most commonly seen in middle-aged women. Approximately 10% of these tumors contain rearrangements of the chromatin-remodeling gene HMGA2 at the chromosome band 12q14.3. Herein, we report on a uterine leiomyoma with a novel HMGA2 fusion gene. A 44-year-old woman presented with a 20-cm mass uterine leiomyoma. From a histological standpoint, the tumor exhibited extensive hyalinization, very low mitotic activity (<1/10 HPH), and no cytologic atypia. Smooth muscle differentiation was confirmed by the expression of smooth muscle actin and desmin. Standard cytogenetic analysis showed the reciprocal translocation t(7;12)(q31.2;q14.3). Fluorescence in situ hybridization analysis confirmed a balanced rearrangement of the HMGA2 locus in 80% of the cells. 3'RACE reverse-transcription polymerase chain reaction identified the fusion of HMGA2 exon 4 to the COG5 locus on 7q31 (component of oligomeric golgi complex 5 isoform). The fusion sequence is predicted to encode a 96-amino acid chimeric protein that retains all three DNA-binding domains (AT hooks) of HMGA2, but that is shorter than the original HMGA2 protein. Since the general structure of the fusion gene is similar to other previously described HMGA2 fusions, its biologic activity is predicted to be likely similar.

HMGA1 and HMGA2 rearrangements in mass-forming endometriosis

Endometriosis is a common gynecologic disorder characterized by ectopic endometrium associated with pelvic pain and infertility. The pathogenesis of endometriosis is unclear, and several genetic, endocrine, immune, and environmental agents have been studied as putative causative factors. However, consistent somatic genetic alterations have not been identified. Rarely, endometriosis presents as a mass lesion with an infiltrative pattern reminiscent of malignancy. We describe cytogenetic and molecular cytogenetic findings of mass-forming endometriosis. The index case of pulmonary endometriosis underwent conventional and molecular cytogenetics analysis. In addition, 16 cases of mass-forming endometriosis, 11 cases of usual endometriosis, and six endometriomas were investigated by fluorescence in situ hybridization (FISH) for HMGA1 and HMGA2 loci, performed on paraffin-embedded thin tissue sections with custom-designed probes. The index patient had an endometriotic lung nodule, with a 46,XX, t(5;6)(q13;p21) karyotype and HMGA1 rearrangement by FISH. A second patient had decidualized endometriosis forming a large abdominal mass and HMGA1 rearrangement by FISH. Of the 15 other cases of mass-forming endometriosis, one had HMGA1 rearrangement and two had HMGA2 rearrangement. The rearrangements were found in the stromal component exclusively. None of the usual endometriosis cases or endometriomas had HMGA1 or HMGA2 rearrangements. In conclusion, mass-forming endometriosis is an uncommon subset of endometriosis that harbors HMGA1 or HMGA2 rearrangements in up to 29% of cases. The present findings support the concept that endometriosis is clonal and that rearrangement of HMGA genes likely contributes to its pathogenesis.

Relevance of miR-21 and miR-143 expression in tissue samples of colorectal carcinoma and its liver metastases

MicroRNAs, which are endogenously expressed regulatory noncoding RNAs, have an altered expression in colorectal cancer. The aim of our study was to assess the relationship of miR-21 and miR-143 expression to the prognostic/clinicopathological features of colorectal carcinoma (CRC) and colorectal liver metastases (CLM). The estimation was performed in 46 paired (tumor and control) tissue samples of CRC. Further, we studied 30 tissue samples of CLM. MiR-21 and miR-143 expressions were quantified by using the quantitative reverse transcription polymerase chain reaction method. Relation of miR-21 and miR-143 expression to disease-free interval (DFI) (Wilcoxon; P = 0.0026 and P = 0.0191, respectively) was recorded. There was shorter DFI in patients with a higher expression of miR-21 and, surprisingly, also in patients with a higher expression of miR-143, which is a putative tumor suppressor. There was a higher expression of miR-21 and lower expression of miR-143 in CRC tissue in comparison with adjacent normal colon tissue (P < 0.0001; P < 0.0001, respectively). Similarly, we observed a higher expression of miR-21 and a lower expression of miR-143 in CLM in comparison with normal colon tissue (P < 0.0001; P < 0.0001, respectively). Our results support the hypothesis about oncogenic function of miR-21 and show its relation to DFI. The role of miR-143 in carcinogenesis seems to be more complex.

Fusion of HMGA1 to the LPP/TPRG1 intergenic region in a lipoma identified by mapping paraffin-embedded tissues

Ordinary lipoma frequently harbors rearrangement of HMGA2. LPP is the most common partner gene to HMGA2, but has not been seen fused to HMGA1. We report the fusion of HMGA1 to the intergenic region between LPP and TPRG1 in a lipoma. Conventional cytogenetic analysis of an abdominal-wall lipoma diagnosed in a 60-year-old woman showed a t(3;6)(q27;p21). Molecular cytogenetic mapping of available paraffin-embedded tissues revealed the fusion of HMGA1 to a 139-kb genomic region between the LPP and TPRG1 loci. No rearrangement of HMGA2 was found. The biological function of this novel fusion could be similar to the role of HMGA2-LPP in tumorigenesis.

Mesenchymal Lesions of the Lower Genital Tract

A variety of site-specific mesenchymal lesions of the lower genital tract may occur, which are often diagnostically challenging because of their morphologic overlap. Some of this morphologic homogeneity presumably stems from a potentially shared origin from the specialized superficial stroma of the distal female genital tract. Despite shared appearances, morphologic distinction remains the gold standard for diagnosis of most of these lesions, as immunoperoxidase staining is often not helpful in their distinction.

Cytogenetics of Mesenchymal Tumors of the Female Genital Tract

A great diversity of chromosome alterations have been reported in mesenchymal tumors of the female genital tract, particularly in the uterus. Some of these alterations specifically identify a certain tumor type. Cytogenetic studies on benign proliferations have not only demonstrated clonal chromosome changes, but have also pointed out clustering of aberrations to specific chromosome regions. For example, distinct cytogenetic subgroups have been described in uterine leiomyomas with overlapping histologic features. These findings may ultimately correlate with specific parameters, such as course of the disease, response to therapy, and recurrence. Moreover, such data may give a clue to an understanding of the biologic basis for distinctive behavior of benign versus malignant mesenchymal proliferations. No specific chromosomal abnormalities have been described in malignant mesenchymal tumors, with the exception of low-grade endometrial stromal sarcomas. This article reviews the information currently available on genetic changes in mesenchymal tumors of the female genital tract and, more specifically, those reported in the uterus, where they have been more frequently studied.

Angiomyofibroblastoma: a rare vulvar tumor

INTRODUCTION

Angiomyofibroblastoma is a rare, benign mesenchymal tumor that occurs mainly in the vulval region of middle age (35-45 years) women.

CASE

We describe a 41-year-old woman, presenting with a 10-cm right vulvar mass and persistent perineal pain lasting 1 month. A surgical excision of the lesion was performed and a large mass with an intact capsule was sent for pathological examination. The results indicated angiomyofibroblastoma.

CONCLUSION

The differential diagnosis between angiomyofibroblastoma (AMF) and aggressive angiomyxoma (AAM) is very important because prognoses are not the same. AMF is a well-circumscribed lesion, with a weak risk of local non-destructive recurrence. AAM is a locally aggressive and infiltrative neoplasm, with a high risk of local aggressive recurrence. Wide excision with a rim of normal tissue is recommended in all cases of vulvar tumors.

Aggressive angiomyxoma with t(12;21) and HMGA2 rearrangement: report of a case and review of the literature

Conventional cytogenetic analysis of an aggressive angiomyxoma of the rectal wall of a 72-year-old woman revealed a translocation between the long arms of chromosomes 12 and 21, with the karyotype 46,XX,t(12;21)(q15;q21.1). Involvement of the HMGA2 gene locus (12q15) was confirmed by fluorescence in situ hybridization using an HMGA2 breakpoint flanking probe set performed on metaphase and interphase cells from an in situ culture of fresh lesional tissue. Karyotypic rearrangements of 12q13 approximately q15 are considered recurrent in aggressive angiomyxoma, although reported in only five previous cases. Translocation partner chromosome 21 is unique to the present case.