Angiosarcoma of the Scalp Mimicking an Inflammatory Scarring Alopecia and Diagnosed on Horizontal Histologic Sections.

While most forms of alopecia neoplastica are attributable to cutaneous metastases from visceral primary malignancies, rarely a diffuse primary skin cancer may present as alopecia. Herein, we present a case of angiosarcoma which clinically mimicked an inflammatory alopecia and was diagnosed by examination of alopecia-protocol horizontal histologic sections. A 72-year-old female presented to her dermatologist with a chief complaint of hair loss and pruritus.

Bone Matrix-forming Tumors.

Bone matrix-forming tumors are a group of neoplasms that exhibit differentiation toward any stage of osteoblast development. Their clinicopathologic features can resemble one another, yet their clinical management may vary significantly. Therefore, appropriate treatment requires accurate diagnosis, which can be challenging, especially with limited biopsy specimens.

Giant Cell-Rich Tumors of the Skeleton.

The accurate diagnosis of giant cell-rich tumors of bone is challenging, especially in limited tissue samples. This diverse group of neoplasms have similar and often ambiguous clinical presentations, radiologic features, and morphologic characteristics. During the last decade, the discovery of pathogenic recurrent genetic alterations has allowed the development of immunohistochemical surrogate markers and FISH assays that can help differentiate the entities of this broad group from one another.

Cutaneous Rosai-Dorfman disease with MAP2K1 mutation, initially mimicking an infection with parasitized histiocytes.

Rarely, Rosai-Dorfman disease (RDD) manifests exclusively in the skin, typically as nodules on the trunk and extremities. Recognition of characteristic histopathologic features enables diagnosis of RDD. A 55-year-old female presented with a 7-year history of cutaneous nodules involving the trunk and extremities.

Mesenchymal neoplasms of the tongue: A clinicopathologic study of 93 cases.

Neoplasms of the tongue are relatively common, and the vast majority are epithelial in phenotype. Although uncommon, a diverse and distinctive array of mesenchymal neoplasms arises in this anatomic site. To increase our understanding of these lesions, we reviewed our experience of MNs of the tongue and described their clinicopathologic features.

Gene of the month: DDIT3.

DNA damage-inducible transcript 3 () gene, mapped to the human chromosome 12q13.3, encodes a protein that belongs to the CCAAT/enhancer-binding protein family of transcription factors. DDIT3 is involved in the proliferative control that responds to endoplasmic reticulum stress in normal conditions, dimerising other transcription factors with basic leucine zipper (bZIP) structural motifs.

Benign and low-grade superficial endothelial cell neoplasms in the molecular era.

Vascular tumors are the most common mesenchymal neoplasms of the skin and subcutis, and they encompass a heterogeneous group with diverse clinical, histological, and molecular features, as well as biological behavior. Over the past two decades, molecular studies have enabled the identification of pathogenic recurrent genetic alterations that can be used as additional data points to support the correct classification of these lesions. The purpose of this review is to summarize the available data related to superficially located benign and low-grade vascular neoplasms and to highlight recent molecular advances with the role of surrogate immunohistochemistry to target pathogenic proteins as diagnostic biomarkers.

Development of squamous cell carcinoma in the setting of chronic discoid lupus erythematosus may be associated with plasmacytoid dendritic cell inflammation.

Discoid lupus erythematosus (DLE) is the most common type of cutaneous lupus and is clinically characterized by alopecia, depigmentation, and scars on sun-exposed skin. Squamous cell carcinoma is a potential long-term complication. The most important risk factor for squamous cell carcinoma development in people with dark skin is chronic scarring and inflammation, such as those seen in long-standing discoid plaques.

Clinicopathologic Spectrum of Secondary Solid Tumors of the Prostate of Nonurothelial Origin: Multi-institutional Evaluation of 85 Cases.

Secondary involvement of the prostate by urothelial or hematolymphoid neoplasms is relatively common and well-described. In contrast, less is known about the clinicopathologic spectrum of secondary solid tumors of the prostate of nonurothelial origin. This study evaluated a series of secondary nonurothelial solid tumors of the prostate diagnosed at 21 institutions.

A review of bubble hair deformity.

Bubble hair deformity is an acquired abnormality characterized by air-filled cavity formations within the hair shaft, usually because of heat damage. Traditionally, bubble hair is diagnosed by visualization of characteristic bubbles under light microscopy. The increased utilization of trichoscopy (scalp dermoscopy) has led to its adoption in the diagnosis of many hair and scalp conditions, including bubble hair deformity.

Highlighting the Diversity of Desmoplastic Small Round Cell Tumor: A Case Series.

Desmoplastic small round cell tumor (DSRCT) is a rare malignant tumor that occurs mainly in the retroperitoneum of children and young adults. In its prototypical form, DSCRT displays characteristic morphology with nested primitive small round cells in a desmoplastic stroma and a distinctive immunophenotype with polyphenotypic differentiation. However, DSCRT can also exhibit a broader clinical, histologic and immunohistochemical spectrum and, therefore, cause diagnostic difficulties.

Development of Chancre-Variant Cutaneous Tuberculosis After BCG Vaccine Administration in a Patient With Migraines.

In countries other than the United States, the BCG vaccine is typically used as a method for preventing childhood tuberculosis; in the United States, the BCG vaccine has gained popularity as a speculated therapy for autoimmune and inflammatory disorders. Research suggests that the vaccine can train the innate immune response, thereby improving symptoms of disorders such as diabetes and fibromyalgia. However, the potential side effects associated with the use of this vaccine are not totally innocuous.

Genomic Landscape of Angiosarcoma: A Targeted and Immunotherapy Biomarker Analysis.

We performed a retrospective analysis of angiosarcoma (AS) genomic biomarkers and their associations with the site of origin in a cohort of 143 cases. Primary sites were head and neck (31%), breast (22%), extremity (11%), viscera (20%), skin at other locations (8%), and unknown (9%). All cases had Next Generation Sequencing (NGS) data with a 592 gene panel, and 53 cases had Whole Exome Sequencing (WES) data, which we used to study the microenvironment phenotype.

Amyloid Arthropathy: A Review.

Amyloid arthropathy is a joint disease associated with systemic amyloidosis. Herein, we present a model case and review the clinicopathologic features and pathophysiology of this disorder. Amyloid arthropathy results from elevation of serum amyloidogenic proteins and their deposition as aggregates in synovial fluid and articular tissues.

Monodactylous Longitudinal Melanonychia: A Sign of Bowen's Disease in Skin of Color.

Introduction: Monodactylous longitudinal melanonychia (LM) may represent both benign and malignant dermatologic disorders. However, squamous cell carcinoma in situ (SCCis) is not commonly considered in this setting.

Case Presentation: In this report, we present 2 cases of SCCis of the nail matrix in patients with skin of color who presented with monodactylous LM involving the lateral aspect of the nail.

Mesenchymal Neoplasms of Salivary Glands: A Clinicopathologic Study of 68 Cases.

Salivary gland neoplasms are uncommon, and most exhibit epithelial differentiation. Mesenchymal neoplasms of the salivary gland are rare, and the incidence ranges from 1.9% to 5%.

Novel fusion genes in spindle cell rhabdomyosarcoma: The spectrum broadens.

Rhabdomyosarcoma (RMS) encompasses a heterogeneous group of tumors with striated muscle differentiation. RMSs are classified as alveolar, embryonal, spindle cell/sclerosing, and pleomorphic types and molecular analysis of these tumors has identified aberrations that are useful in their further subclassification. Spindle cell rhabdomyosarcoma (SpRMS) is uncommon and has been described with VGLL2 fusions, EWSR1/FUS-TFCP2 rearrangements, and myoD1 mutations-the mutations are associated with significantly different prognoses.

Unexpected Primary Extranodal Marginal Zone Lymphoma of Bone in Amputation and Arthroplasty Specimens.

Objectives: Amputation due to gangrene and arthroplasty for degenerative joint disease are common orthopedic procedures and are expected to increase as populations age. Histopathologic examination of these specimens can identify unsuspected diseases.

Methods: We reviewed gangrenous amputations and large joint arthroplasty specimens for diagnosis of unexpected lymphoma, January 2014 to January 2020.

Primary Sarcomas of the Larynx: A Clinicopathologic Study of 27 Cases.

Primary sarcomas of the larynx are rare and are associated with diagnostic and treatment challenges. Studies of these tumors are limited, and most examples have been reported as small series. To further increase our understanding of laryngeal sarcomas, we reviewed our experience of an adult cohort.

Cutaneous Presentation of T-Cell Prolymphocytic Leukemia Mimicking Dermatomyositis.

T-cell prolymphocytic leukemia (TPLL) is a rare form of leukemia by T lymphocytes at a post-thymic intermediate stage of development with an α/β immunophenotype. Facial involvement is common in TPLL and displays significant heterogeneity of the lesions' description and location. TPLL also contains a wide array of histology findings, cell cytology, and molecular studies.

Identification of EWSR1-NFATC2 fusion in simple bone cysts.

Aims: Simple bone cysts are benign intramedullary tumours primarily involving the long bones in skeletally immature individuals. Several mechanisms have been proposed for their pathogenesis. Although the diagnosis is typically straightforward, the interpretation can be problematic, because of superimposed fracture causing them to resemble aneurysmal bone cysts and other tumours.