Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is characterized as inflammation of small-sized to medium-sized blood vessels and encompasses several clinicopathologic entities including granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis, and renal-limited ANCA-associated vasculitis. Over the past several decades, significant progress has been made in understanding the pathophysiology of ANCA-associated vasculitis. Although neutrophils contain a multitude of granular proteins, clinically significant autoantibodies are only recognized against myeloperoxidase and proteinase 3, both of which are present in the azurophilic granules. The propensity to develop these antibodies depends on a variety of predisposing factors such as microbial infection, genetic factors, environmental agents, and therapeutic drugs among others. These factors are usually associated with production of proinflammatory cytokines with capacity to prime the neutrophils. As a result a high proportion of neutrophils in circulation may be primed resulting in exposure of cytoplasmic proteins including myeloperoxidase and proteinase 3 on the surface of the neutrophils. Primed neutrophils are activated by interaction with ANCA in circulation. Activated neutrophils attach to and transmigrate through endothelium and accumulate within the vessel wall. These neutrophils degranulate and produce reactive oxygen radicals and ultimately die, causing tissue injury. Endothelial injury results in leakage of serum proteins and coagulation factors causing fibrinoid necrosis. B cells produce ANCAs, as well as neutrophil abnormalities and imbalances in different T-cell subtypes with excess of Th17, which perpetuate the inflammatory process.

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Wilms tumor (WT) is the most common neoplasm of the kidney in children. It is an embryologic tumor that histologically mimics renal embryogenesis and is composed of a variable mixture of stromal, blastemal, and epithelial elements. Nephrogenic rests, generally considered to be precursor lesions of the WT, are foci of the embryonic metanephric tissue that persist after the completion of renal embryogenesis. These are classified as perilobar and intralobar based on their location and maybe present as single or multiple foci. Intralobar and perilobar rests and the tumors arising from these rests differ morphologically and are characterized by 2 different sets of genetic abnormalities involving 2 adjacent foci, WT1 and WT2, on the short arm of chromosome 11. WTs arising in the intralobar rests tend to be stromal predominant and have a mutation or deletion of WT1. Germline mutation in WT1 may be associated with syndromic conditions such as WAGR and Denys-Drash syndromes. Perilobar rests and their corresponding tumors usually have loss of imprinting/loss of heterozygosity involving WT2, which contains several parentally imprinted genes. Loss of function of these genes, if present constitutionally, may be associated with Beckwith-Wiedemann syndrome or may result in isolated hypertrophy. Abnormalities in several other genes may also be seen in WT. These include WTX, (on chromosome X), CTNNB1 (chromosome 3), and TP53 (chromosome 17) among others. WT with loss of heterozygosity at 1p and 16q may have poor prognosis, requiring aggressive therapy. Treatment modalities for WT have evolved over many decades, primarily through the efforts of Dr J Bruce Beckwith at National WT study. This work is now being carried out by Children Oncology Group in North America and International Society of Pediatric Oncology in Europe. Although their therapeutic approaches are somewhat different, both have reported excellent results with equally high cure rates.

Sertoli-Leydig cell tumor (SLCT) of ovary is an exceedingly unusual neoplasm that belongs to a group of sex cord-stromal tumors of ovary and accounts for less than 0.5% of all primary ovarian neoplasms. Very few case reports have been documented in the literature so far. Herein, we report a case of primary poorly differentiated ovarian Sertoli-Leydig cell tumor (SLCT) involving the left ovary in a 16-year-old single woman who presented with a 3-month history of a pelviabdominal mass, acne, hirsutism, and menstrual irregularities. In addition, a literature review on ovarian SLCTs is provided.

Cases that meet biopsy criteria for active surveillance yet have perineural invasion showed no significant difference from those without perineural invasion in terms of adverse findings at radical prostatectomy. Patients with perineural invasion who meet criteria for active surveillance should not be excluded from this treatment option.