Reactive Lymphadenopathies.

Lymphadenitis in the pediatric population frequently is benign and self-limited, often caused by infections. In children with refractory symptoms, lymph node biopsy may be indicated to rule out malignancy or obtain material for culture. Acute bacterial infections typically show a suppurative pattern of necrosis with abscess formation. Viral infections are associated with nonspecific follicular and/or paracortical hyperplasia. Granulomatous inflammation is associated with bacterial, mycobacterial, and fungal infections. Toxoplasma lymphadenitis displays follicular hyperplasia, monocytoid B-cell hyperplasia, and clusters of epithelioid histiocytes. Autoimmune and noninfectious inflammatory disorders are included in differential diagnosis of lymphadenitis. Infectious mononucleosis and Kikuchi-Fujimoto lymphadenitis may mimic Hodgkin and non-Hodgkin lymphomas.

Hepatic uterus-like mass misdiagnosed as hepatic abscess.

BACKGROUND: Hepatic endometriosis/uterus-like mass is rare and may be overlooked during hepatic cyst workups. We report a case of uterus-like mass, misdiagnosed as hepatic abscess. CASE REPORT: A 47-year-old woman developed abdominal pain and vomiting. Infectious colitis with hepatic abscess was diagnosed, and remained antibiotic-refractory. Fine-needle aspiration and core biopsies showed benign contents. The patient presented to our institution with symptoms and normal blood work. Laparoscopic excision demonstrated a 1.4-cm cyst composed of endometrial glands (estrogen receptor+ and progesterone receptor+) and stroma (CD10+) with smooth muscle actin (SMA+), arranged in an organoid fashion. The patient, status-post hysterectomy, had no history or symptoms of endometriosis. CONCLUSION: This rare case illustrates the merit of considering uterus-like mass/endometriosis in the differential diagnosis of antibiotic-refractory hepatic cysts. Cyst heterogeneity may confound needle biopsy. We report the first instance of a hepatic uterus-like mass, with a review of related entities, postulated histogenesis, and important clinical associations.

Hemophagocytic lymphohistiocytosis: an update on diagnosis and pathogenesis.

Hemophagocytic lymphohistiocytosis (HLH) is a frequently fatal and likely underdiagnosed disease involving a final common pathway of hypercytokinemia, which can result in end-organ damage and death. Although an early diagnosis is crucial to decrease mortality, the definitive diagnosis is often challenging because of the lack of specificity of currently accepted diagnostic criteria and the absence of confirmatory gold standards. Because of the wide range of laboratory assays involved in the diagnosis of HLH, practicing pathologists from a broad spectrum of clinical specialties need to be aware of the disease so that they may appropriately flag results and convey them to their clinical counterparts. Our article summarizes these new advances in the diagnosis of HLH and includes a review of clinical findings, updated understanding of the pathogenesis, and promising new testing methods.