Determining the Optimal Number of Core Needle Biopsy Passes for Molecular Diagnostics.

PURPOSE: The number of core biopsy passes required for adequate next-generation sequencing is impacted by needle cut, needle gauge, and the type of tissue involved. This study evaluates diagnostic adequacy of core needle lung biopsies based on number of passes and provides guidelines for other tissues based on simulated biopsies in ex vivo porcine organ tissues. METHODS: The rate of diagnostic adequacy for pathology and molecular testing from lung biopsy procedures was measured for eight operators pre-implementation (September 2012-October 2013) and post-implementation (December 2013-April 2014) of a standard protocol using 20-gauge side-cut needles for ten core biopsy passes at a single academic hospital. Biopsy pass volume was then estimated in ex vivo porcine muscle, liver, and kidney using side-cut devices at 16, 18, and 20 gauge and end-cut devices at 16 and 18 gauge to estimate minimum number of passes required for adequate molecular testing. RESULTS: Molecular diagnostic adequacy increased from 69% (pre-implementation period) to 92% (post-implementation period) (p < 0.001) for lung biopsies. In porcine models, both 16-gauge end-cut and side-cut devices require one pass to reach the validated volume threshold to ensure 99% adequacy for molecular characterization, while 18- and 20-gauge devices require 2-5 passes depending on needle cut and tissue type. CONCLUSION: Use of 20-gauge side-cut core biopsy needles requires a significant number of passes to ensure diagnostic adequacy for molecular testing across all tissue types. To ensure diagnostic adequacy for molecular testing, 16- and 18-gauge needles require markedly fewer passes.

Uterine Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy).

We report a unique case of Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) involving the uterus. A 63-yr-old female with a history of parathyroid adenoma and cavernous sinus meningioma underwent total abdominal hysterectomy for a possible uterine malignancy. The histologic findings consisted of a nodular, mass-like infiltration of the myometrium by clusters, cords, and sheets of CD163-positve, S100-positive histiocytes with lymphocytophagocytosis (emperipolesis). The cells were negative for CD1a and langerin. Occasional plasma cells and erythrocytes were also present. Most of the histiocytes had pale, vacuolated, or foamy cytoplasm. In all cases, the nuclei were small and eccentric. No mitotic figures were identified. Two prior cases of Rosai-Dorfman disease have been reported in the female genital tract: 1 in the cervix and 1 in the bilateral ovaries. Rosai-Dorfman disease should be added to the differential diagnosis of histiocyte-rich lesions in the female genital tract. The diagnosis should be strongly considered in the presence of the characteristic histology with lymphocytophagocytosis (emperipolesis). A limited immunohistochemical panel consisting of CD163, S100, and CD1a and/or langerin will confirm the diagnosis in most cases.