Sporadic superficial angiomyxomas demonstrate loss of PRKAR1A expression

Update on immunohistochemistry in bone and soft tissue tumors: Cost-effectively replacing molecular testing with immunohistochemistry

Soft tissue tumors form part of a challenging domain in diagnostic pathology owing to their comparative rarity, astonishing histologic diversity, and overlap between entities. Many of these tumors are now known to be defined by highly recurrent, or, in some instances, unique molecular alterations. Insights from gene profiling continue to elucidate the wider molecular landscape of soft tissue tumors; many of these advances have been co-opted by immunohistochemistry (IHC) for diagnostic applications. There now exists a multitude of antibodies serving as surrogate markers of recurrent gene fusions, amplifications, and point mutations, which, in certain settings, can replace the need for more resource and time-intensive cytogenetic and molecular genetic analyses. IHC presents many advantages including rapid turnaround time, cost-effectiveness, and interpretative reproducibility. A sensible application of these immunohistochemical markers complemented by a working knowledge of the molecular pathogenesis of bone and soft tissue tumors permits accurate diagnosis in the majority of cases. In this review, we will outline some of these biomarkers while emphasizing molecular correlates and highlighting interpretative challenges and pitfalls.

Concurrent PTEN and PDGFRB Alterations Characterize Storiform Collagenoma

Storiform collagenoma is a rare mesenchymal skin tumor that is composed of thickened collagen bundles arranged in a characteristic storiform pattern with a relatively hypocellular CD34-positive spindle cell component. Storiform collagenoma is most often sporadic, but multiple lesions can occur in Cowden syndrome, which is characterized by germline alterations in PTEN (phosphatase and tensin homolog) on chromosome 10. Here, we investigated the molecular pathogenesis of storiform collagenoma using a targeted next-generation DNA sequencing platform, including 5 sporadic cases and one case associated with Cowden syndrome. Recurrent PTEN alterations were identified in all cases, with biallelic PTEN inactivation observed in the case associated with Cowden syndrome and one sporadic case. Unexpectedly, we also identified recurrent activating mutations in the platelet-derived growth factor receptor beta ( PDGFRB ) gene. This included a missense substitution in the D5 Ig-like domain of PDGFRB in the Cowden syndrome-associated case. In addition, we report missense alterations in the juxtamembrane domain of PDGFRB in 4 of 5 (80%) sporadic cases, including mutations that have been previously described in sporadic myofibroma and myopericytoma. Therefore, we confirm the neoplastic nature of storiform collagenoma, we expand the spectrum of reported PDGFRB alterations in mesenchymal tumors and we suggest a possible collaborative role for PTEN and PDGFRB in the pathogenesis of storiform collagenoma.

Myxofibrosarcoma in adolescents and young adults: a clinicopathologic study of 17 cases

Myxofibrosarcoma is a locally aggressive sarcoma that characteristically arises in the extremities of older patients. Cases arising at a younger age are rare, leading to diagnostic challenges. Our aim was to study the clinicopathologic features of myxofibrosarcoma in patients aged ≤40 years. Cases of myxofibrosarcoma and myxoid malignant fibrous histiocytoma arising in patients aged ≤40 years with clinical follow-up were collected from multiple institutions. Hematoxylin and eosin slides were evaluated for mitoses, necrosis, and epithelioid areas. Seventeen cases were identified (13 females, 4 males; 16-39 years; median 32 years), tumors ranged from 2.2 to 34 cm (median 4.1 cm). Anatomic sites included proximal extremity (9), distal extremity (4), trunk (1), and head/neck (3). Ten were superficial, and 6 were deep-seated. Three cases were predominantly epithelioid. In untreated resection specimens, 6 were FNCLCC grade 1, 4 grade 2, and 2 grade 3. Follow-up (6-204 months, median 36 months) revealed that 2 patients experienced local recurrences, 1 distant metastasis, and 2 patients both. The 5-year overall survival (OS) and event-free survival (EFS) were 84% and 55.9%, respectively. Tumor depth and necrosis were correlated with inferior OS (P = .025, P = .005), while tumor depth was also associated with worse EFS (P = <.001). We conclude that myxofibrosarcomas arising in adolescents and young adults show similar behavior compared to their older adult counterparts. Tumor depth and necrosis are poor prognostic factors in myxofibrosarcoma in this age group. Awareness that myxofibrosarcoma can rarely present in this population is important for accurate diagnosis.

Superficial Angiomyxoma in an Uncommon Area: A Case Report

Superficial angiomyxomas, also known as cutaneous myxomas, are rare, benign soft tissue tumors that present as papulonodular or polypoid, asymptomatic, slow-growing lesions. They typically occur in the head, neck, trunk, and extremities of adults and may be isolated tumors or part of the Carney Complex. We present a case of SA with an uncommon area of presentation and a brief discussion of the importance of ruling out the presence of systemic syndromes such as the Carney Complex.

Umbilical Cord Diseases Affecting Obstetric and Perinatal Outcomes

BACKGROUND

(1) The aim of this article is to describe the physiopathology underlying umbilical cord diseases and their relationship with obstetric and perinatal outcomes. (2) Methods: Multicenter case series of umbilical cord diseases with illustrations from contributing institutions are presented. (3) Results: Clinical presentations of prenatal ultrasound findings, clinical prenatal features and postnatal outcomes are described. (4) Conclusions: Analysis of our series presents and discusses how umbilical cord diseases are associated with a wide variety of obstetric complications leading to a higher risk of poor perinatal outcomes in pregnancies. Knowing the physiopathology, prenatal clinical presentations and outcomes related to umbilical diseases allow for better prenatal counseling and management to potentially avoid severe obstetric and perinatal complications.

Angiomyxoma of the Breast: A Clinicopathologic Analysis of 40 Cases

Superficial angiomyxoma is an uncommon benign mesenchymal neoplasm that usually arises in dermis/subcutis of the extremities or trunk. Some tumors are associated with Carney complex. When arising in breast, these tumors are not well-recognized, mainly due to a lack of uniform nomenclature in the literature. This study therefore aims to improve recognition of angiomyxomas of the breast region. Forty cases were identified: demographics, presence of Carney complex, imaging and histologic features, PRKAR1A expression, and outcomes were evaluated. There were 22 female and 18 male patients (median age 40 years, range: 14 to 72). Most tumors presented as slowly-growing masses (77%). All but one were solitary, and median size was 1.5 cm. Tumors were superficial (dermal/subcutaneous) in 52.5% and deep/parenchymal in 47.5%. Nine involved the nipple-areola complex. All showed characteristic features of superficial angiomyxoma: poorly circumscribed, hypocellular, myxoid neoplasms with lobulated (55%) or infiltrative (45%) architecture, bland spindled fibroblasts, prominent thin-walled vessels, and admixed neutrophils. Tumors involving the nipple-areola complex infiltrated through areolar smooth muscle, and deep/parenchymal tumors showed entrapment of lobules mimicking myxoid fibroadenoma. Mitoses were typically absent, as was significant atypia. Cystic change was common. Two-thirds showed loss of PRKAR1A expression by immunohistochemistry. Two patients had Carney complex (7%). Recurrence after incomplete excision occurred in 1 patient. Angiomyxoma of breast may arise at superficial, nipple-areola or deep/parenchymal locations, where it can be difficult to recognize classic histologic features. Loss of expression of PRKAR1A is not invariable, but may be a helpful diagnostic clue. Recognizing angiomyxoma is important for 2 reasons: first, the recurrence rate is low and therefore wide excision is not essential, and second, it may allow detection of Carney complex in some patients.

Pediatric Vulvar Superficial Angiomyxoma: A Case Report With Clinical, Radiological, and Anatomopathological Characterization and a Comprehensive Review of the Literature

Superficial angiomyxoma is characterized as a benign, slow-growing vascular cutaneous myxoma. A 6-year-old Arab girl with no medical history presented with a vulvar tumor located on the left labia majora. The lesion was present since birth, but it had significantly increased over the last 6 months. She did not have any associated symptoms. Physical examination revealed an exophytic tumor of the left labia majora, which measured 5 cm in its major axis. Doppler ultrasound study showed a mass with abundant arterial and venous vascularization, and magnetic resonance imaging showed a highly vascular contrast-enhanced mass with well-delimited margins, which depended on the labia majora. A macroscopically complete resection was performed, achieving a tension-free primary closure. Histologically, the lesion was characterized as a well-demarcated superficial tumor with thin-walled vessels and myxoid stroma, S100 (−), CD34 (+), vimentin (+), and actin (+). The final histopathological diagnosis was superficial angiomyxoma. The literature review of this entity in the pediatric population shows a predominance of this lesion in the vulvar location. Local recurrence has been described. Loss of PRKAR1A expression may be involved in the pathogenesis of superficial angiomyxoma.

Changing Course of an Umbilical Cord Mass - Chasing the Diagnosis of Angiomyxoma

Angiomyxoma of the umbilical cord is a rare benign vascular malformation with potential for fetal morbidity and mortality. Gross and histologic features of this lesion are identical to those described as "hemangioma," however "angiomyxoma" is a preferable term as current practice restricts the term "hemangioma" to infantile capillary proliferations that express glucose transporter 1. Here we describe the case of an umbilical cord angiomyxoma with associated pseudocysts diagnosed after delivery at 33 weeks. It presented as a heterogeneous-appearing mass near the fetal cord insertion and mimicked serious fetal anomalies throughout gestation. We found fetal MRI helpful for monitoring this lesion, narrowing the differential, and informing management. Proximity to the fetal end of the cord and uncertainty about diagnosis also required surgical resection of the mass after delivery with umbilicoplasty.

[Superficial angiomyxoma in nasal vestibule: a case report]

This paper reported a case of superficial angiomyxoma in the region of the nasal vestibule. The clinical manifestation was swelling of the left nasal vestibular skin, while paranasal sinus CT showed swell soft tissue in the anterior and superior region to the left maxilla. Under general anesthesia, the left nasal vestibular mass was resected under nasal endoscopy. The postoperative pathological diagnosis was superficial angiomyxoma. The patient underwent a CT scan of the paranasal sinuses 4 months after the operation, and there was no recurrence of the tumor.

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..

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Soft Tissue Tumors

The fifth (5th) edition of the World Health Organization (WHO) Classification of Head and Neck Tumors introduces a new chapter dedicated to soft tissue neoplasms commonly affecting the head and neck. While the diversity, rarity, and wide anatomic range of soft tissue tumors precludes a discussion of all entities that may be found in the head and neck, the addition of this new chapter to the head and neck "blue book" aims to provide a more comprehensive and uniform reference text, including updated diagnostic criteria, of mesenchymal tumor types frequently (or exclusively) arising at head and neck sites. Since publication of the previous edition in 2017, there have been numerous advances in our understanding of the pathogenesis of many soft tissue tumors which have facilitated refinements in tumor classification, identification of novel entities, development of diagnostic markers, and improved prognostication. This review will provide a focused discussion of the soft tissue tumors included in the 5th edition WHO Head and Neck classification, with an emphasis on updates.

Superficial Angiomyxomas Frequently Demonstrate Loss of Protein Kinase A Regulatory Subunit 1 Alpha Expression: Immunohistochemical Analysis of 29 Cases and Cutaneous Myxoid Neoplasms With Histopathologic Overlap

Superficial angiomyxomas (SAMs) are benign cutaneous tumors that arise de novo and in the setting of the Carney complex (CC), an autosomal dominant disease with several cutaneous manifestations including lentigines and pigmented epithelioid melanocytomas. Although most SAM do not pose a diagnostic challenge, a subset can demonstrate histopathologic overlap with other myxoid tumors that arise in the skin and subcutis. Traditional immunohistochemical markers are of limited utility when discriminating SAM from histopathologic mimics. Since protein kinase A regulatory subunit 1 alpha (PRKAR1A) genetic alterations underlie most CC cases, we investigated whether SAM demonstrate loss of PRKAR1A protein expression by immunohistochemistry. In our series, 29 SAM, 26 myxofibrosarcoma, 5 myxoid dermatofibrosarcoma protuberans, 11 superficial acral fibromyxomas, and 18 digital mucous cysts were characterized. Of the 29 SAM examined in this study, 1 was associated with documented CC in a 5-year-old girl. SAM tended to arise in adults (mean 49.7 y; range: 5 to 87 y). Loss of PRKAR1A was seen in 55.2% of cases (16/29) and had a male predilection (87.5%, 12/16). PRKAR1A-inactivated SAM demonstrated significant nuclear enlargement (100%, 16/16 vs. 23.1%, 3/13), multinucleation (81.3%, 13/16 vs. 23.1%, 3/13), and presence of neutrophils (43.8%, 7/16 vs. 0%, 0/13). In contrast, PRKAR1A was retained in all cases of myxofibrosarcoma (100%, 26/26), myxoid dermatofibrosarcoma protuberans (100%, 5/5), superficial acral fibromyxomas (100%, 11/11), and digital mucous cyst (100%, 18/18). Taken together, PRKAR1A loss by immunohistochemistry can be used as an adjunctive assay to support the diagnosis of SAM given the high specificity of this staining pattern compared with histopathologic mimics.