Rare Cutaneous Primary Presentation of Extracavitary Primary Effusion Lymphoma.

Primary effusion lymphoma (PEL) is a rare and aggressive B-cell lymphoma typically associated with human herpesvirus 8 (HHV-8) and Epstein-Barr virus infections. It classically presents as a malignant effusion in body cavities, but rarely presents with an extracavitary variant characterized by solid tumors in lymph nodes or extranodal sites such as the gastrointestinal tract, skin, lungs, and nervous system. This case report describes an unusual presentation of primary cutaneous extracavitary PEL in an HIV-positive patient that has only been reported in 8 cases previously.

Benign cervical schwannoma with tracheal invasion.

Schwannomas commonly develop in the cervical region, 25% - 45% of cases are diagnosed in this anatomical region. Tracheal neurogenic tumors are exceedingly rare and can be misdiagnosed as invasive thyroid carcinomas or other infiltrating malignancies when present at the level of the thyroid gland. Here, we present a case of synchronous benign cervical schwannoma with tracheal invasion and papillary thyroid carcinoma in a patient who was initially hospitalized for COVID-19.

Clinicopathological characteristics of endometrial carcinomas according to DNA mismatch repair protein status.

DNA mismatch repair protein deficiency (MMRd) in endometrial carcinoma is associated with the risk of Lynch syndrome and response to immune checkpoint inhibitors. It is also related to microsatellite instability and corresponds to a molecular subtype of endometrial tumor with an unclear prognosis. Here, we evaluated the clinicopathological characteristics and prognosis of 312 consecutive endometrial carcinoma cases submitted to complete surgical staging at a single institution.

Fibroblastic reticular cell tumour of the internal iliac lymph node presenting as a hypervascular lesion and mimicking a pseudoaneurysm: an extremely rare diagnosis.

A woman in her 50s presented with a rounded and hypervascular lesion in the right internal iliac lymph node chain, contacting with small branches of the anterior division of the internal iliac artery. Since the lesion matched the blood arterial pool in CT and the patient exhibited multiple vascular abnormalities that suggested segmental arterial mediolysis, a pseudoaneurysm hypothesis was initially made. Arteriography was realised due to the intention for embolisation of the pseudoaneurysm, but the dynamic behaviour during the exam suggested a hypervascular tumour more.

A case of aleukemic leukemia cutis after COVID-19 infection presenting as facial rash.

Aleukemic leukemia cutis (ALC) is a rare condition that is characterized by leukemic cells in the skin before presenting in the peripheral blood or bone marrow. We report a case of a 43-year-old woman who underwent assessment for bilateral facial nodules arising 1 month after COVID-19 infection. A punch biopsy specimen showed a malignant neoplasm primarily composed of immature blasts dissecting through the collagen in the dermis, concerning for myeloid sarcoma versus leukemia cutis.

Overexpression of CLDN16 in ovarian cancer is modulated by PI3K and PKC pathways.

Epithelial ovarian cancer (EOC) is the gynecological malignant tumor of poorest prognosis and higher mortality rate. Chemotherapy is the base of high-grade serous ovarian cancer (HGSOC) treatment; however, it favors the emergence of chemoresistance and metastasis. Thus, there is an urge to search for new therapeutic targets, such as proteins related to cellular proliferation and invasion.

Histopathologic and molecular characterization of BAP-1-inactivated melanoma.

Background: BRCA1-associated protein 1 (BAP-1) is a deubiquitylase that functions as a tumor suppressor, regulating multiple cellular processes including cell cycle control, differentiation, cell death, and DNA repair. BAP-1-inactivated melanocytic tumors (BIMTs) have recently been described and are characterized by epithelioid cytomorphology, are often clonal in appearance, and typically do not recur or show malignant transformation on follow-up.

Aim: To describe the histopathologic and molecular characterization of five cases of BAP-1-inactivated cutaneous malignant melanomas.

Teratocarcinosarcoma-Like and Adamantinoma-Like Head and Neck Neoplasms Harboring NAB2::STAT6: Unusual Variants of Solitary Fibrous Tumor or Novel Tumor Entities?

The archetypal solitary fibrous tumor (SFT) features fibroblastic cells with varying cellularity without any particular architectural arrangement in a collagenous matrix, with staghorn vessels, CD34 and STAT6 expression, and NAB2::STAT6. To date, this fusion is thought to be specific for SFT. With more routine use of fusion gene panels, the histologic diversity of NAB2::STAT6-positive tumors is increasingly appreciated.

Malignant mesothelioma of the tunica vaginalis testis: A rare cause of hydrocele.

Mesotheliomas of the tunica vaginalis testis are very uncommon tumors, with rare cases published in the literature. This report demonstrates a case in with such a tumor was diagnosed in a 50-year-old man who presented to the emergency room with mild, acute scrotal pain and swelling, without previously known scrotal pathology. It is noted that sonographers should be aware of the typical characteristics that allow for suspecting malignancy in scrotal sonography performed in the emergency setting; this was particularly important in this case.

Surgically treated mediastinal fat necrosis: an exception to conservative treatment.

Mediastinal fat necrosis is an important differential diagnosis for acute chest pain in previously healthy patients. Imaging examination is essential to establish this diagnosis, as physical examination can be unhelpful and laboratory tests are non-specific. The treatment of choice is conservative, with non-steroidal anti-inflammatory drugs; surgery is reserved for a few selected cases.

Secondary skin involvement in classic Hodgkin lymphoma: Results of an international collaborative cutaneous lymphoma working group study of 25 patients.

Background: Cutaneous involvement by classic Hodgkin lymphoma (CHL) is an extraordinarily rare phenomenon in the current era. To date, no single large case series of cutaneous involvement by Hodgkin lymphoma has ever been reported in the literature.

Methods: A comprehensive search for cases designated "skin" and "Hodgkin" was performed at different institutions between 1990 and 2020.

Consensus on Screening, Diagnosis, and Staging Tools for Prostate Cancer in Developing Countries: A Report From the First Prostate Cancer Consensus Conference for Developing Countries (PCCCDC).

Purpose: To generate and present the survey results on critical issues relevant to screening, diagnosis, and staging tools for prostate cancer (PCa) focused on developing countries.

Methods: A total of 36 of 300 questions concern the main areas of interest of this paper: (1) screening, (2) diagnosis, and (3) staging for various risk levels of PCa in developing countries. A panel of 99 international multidisciplinary cancer experts voted on these questions to create recommendations for screening, diagnosing, and staging tools for PCa in areas of limited resources discussed in this manuscript.

PD-1 and PD-L1 Immunohistochemistry as a Diagnostic Tool for Classic Hodgkin Lymphoma in Small-volume Biopsies.

It is becoming increasingly important to obtain detailed diagnostic information on small-volume tissue biopsies, such as core needle biopsies. This is particularly crucial in the workup and diagnosis of classic Hodgkin lymphoma (CHL) and other morphologically similar lymphomas such as T-cell/histiocyte-rich large B-cell lymphoma (THRLBL), where small-volume lymph node biopsies often represent the frontline tissue source, and the differential diagnosis includes a reactive process. Immunohistochemical markers could be helpful to differentiate CHL from reactive lymph node changes (RLN) in this setting.

Metastatic Biphasic Primitive Tumor in the Mandible of a Child.

Pediatric mandibular tumors present an aggressive biological behavior and difficult diagnosis. A wide range of odontogenic and nonodontogenic tumors comprise the spectrum of these lesions. We report a case of a 1-year-old male child patient showing facial asymmetry symptomatic of an expansive lesion extending throughout the body and ramus of the left hemimandible with a diameter of 8 cm.

Clear Cell Sarcoma With Cutaneous Presentation in a 4-Year-Old Boy.

We report a case of a 4-year-old Brazilian boy, who presented with an erythematous and painful nodule involving the skin of his left arm. Immunohistochemistry was performed for S100, SOX10, CD34, desmin, SMA, HMB-45, CD1a, and CD163, and fluorescence in situ hybridization for EWSR1 gene rearrangement using a break-apart probe was completed. Immunohistochemistry showed bland spindle cells with "floret-like" appearance simulating a giant cell fibroblastoma; tumor cells were positive for S100 and SOX10; neoplastic cells were negative for CD34, desmin, SMA, HMB-45, CD1a, and CD163; and fluorescence in situ hybridization showed an EWSR1 gene rearrangement.

MUC4 Expression in Angiomatoid Fibrous Histiocytoma.

Angiomatoid fibrous histiocytoma (AFH) is a rarely metastasizing neoplasm that typically occurs in the deep dermis and subcutis of the extremities of young patients, characterized by a t(2;22) translocation involving EWSR1 and CREB1. Because of its distinctive histologic features, the diagnosis of AFH is generally straightforward, although the immunohistochemistry (IHC) findings are relatively nonspecific. We recently encountered a case of primary cranial AFH that showed strong MUC4 IHC expression, which has not yet been reported previously.

Novel SS18-NEDD4 gene fusion in a primary renal synovial sarcoma.

We report a primary renal synovial sarcoma with a novel gene fusion and unusual morphology. The patient was a 35-year-old female who was found to have a 5 cm hypocellular, myxoid spindle cell renal neoplasm that subtly permeated amongst native renal tubules. The tumor cells showed elongated hyperchromatic nuclei with ill-defined pale cytoplasm, lacking significant mitotic activity or necrosis.

Macrocystic (Mammary Analogue) Secretory Carcinoma: An Unusual Variant and a Pitfall in the Differential Diagnosis of Cystic Lesions in the Head and Neck.

Mammary analogue secretory carcinoma (MASC) is a relatively recently described salivary gland adenocarcinoma characterized by ETV6-NTRK3 gene fusion and in most cases indolent clinical behavior. The majority of tumors show an admixture of microcystic, solid, and tubular growth patterns but only a few cases with dominant macrocystic growth have been reported. We report 15 cases of macrocystic MASC.

miR‑29 promoter and enhancer methylation identified by pyrosequencing in Burkitt lymhoma cells: Interplay between MYC and miR‑29 regulation.

Deregulation of microRNA expression plays a significant role in several cancer types including Burkitt lymphoma (BL). MicroRNA genes may be regulated through epigenetic mechanisms, such as specific histone modifications and/or DNA methylation of CpG islands in promoter regions, or by regions that are located next to microRNA genes. Given the regulatory role of MYC in miR‑29 expression, methylation as an additional mechanism for miR‑29 silencing was investigated.