7 December 2020: Textbook Updates

We have posted updates of the following topics:

Breast > Fibrocystic changes > Adenomyoepithelial adenosis
by Julie M. Jorns, M.D.
Topic summary: Uncommon variant of adenosis with lobulocentric proliferation of both epithelial and myoepithelial cells. Wide age range but most frequent in third to fourth decades. Diagnosis is based on histologic examination of tissue with or without immunohistochemistry. Radiology may show asymmetry, architectural distortion or mass with irregular margins, with or without microcalcifications. Prognostic factors unknown but progression to malignancy may be associated with older age (> 50 years) and mass on imaging. Excision recommended due to possibility of recurrence and association with malignancy.

CD markers > CD70
by Frido Bruehl, M.D., Christian M. Schürch, M.D., Ph.D.
Topic summary: Ligand to CD27 that is transiently upregulated upon stimulation of immune cells and delivers a costimulatory signal to T cells. Expressed on various solid tumors and hematolymphoid malignancies and may impart a poor prognosis. Tumor necrosis factor ligand superfamily member 7 (TNFSF7). Targeting CD70 has shown promise in xenograft models and a phase 1 study using the monoclonal antibody cusatuzumab. Interpretation through membranous and cytoplasmic staining. No current clinical use by pathologists.

Lung > Neuroendocrine tumors > Atypical carcinoid
by Andréanne Gagné, M.D., M.Sc., Philippe Joubert, M.D., Ph.D.
Topic summary: Well differentiated neuroendocrine carcinoma with atypical features. Defined as neuroendocrine tumors with 2 – 10 mitoses per 2 mm² or foci of necrosis. Can be found anywhere from the trachea to the distal bronchioles. More frequent in females (69%) and Caucasians. Mean age at diagnosis is 65 years. Definitive diagnosis of atypical carcinoid can only be made on a surgical resection, unless necrosis or increased mitotic activity is seen. Complete surgical resection is the most efficient treatment for localized disease and has a significant impact on prognosis.

Lymph nodes & spleen, nonlymphoma > Lymph node & spleen-nonlymphoid neoplasms > Indeterminate cell histiocytosis / indeterminate dendritic cell tumor
by Mina Haghighi Abyaneh, M.D., Hina Mohsin, M.D., Ryanne A. Brown, M.D., M.B.A.
Topic summary: Indeterminate cell histiocytosis (ICH) is an extremely rare neoplastic proliferation of cells of dendritic / histiocytic lineage that share immunophenotypic features of Langerhans cells but lack Birbeck granules and langerin expression. Cutaneous involvement (88%) is most common, with rare organ or lymph node involvement. Rare neoplasm, with 85 cases reported between 1985 – 2016. Etiology remains uncertain. Cases restricted to the skin typically behave indolently. Treatment involves surgical excision for isolated lesions.

Methods (molecular, IHC, frozen) > Molecular > FISH > FISH overview
by Ana Caramelo, B.Sc., António Polónia, M.D., Ph.D.
Topic summary: Detection of specific nucleic acid sequences (DNA / RNA). Visualization of signals in the cell or tissue (in situ), by either digital imaging or manual microscopy. Fluorescence ISH (FISH) involves direct detection of a fluorescent labeled probe. Bright-field ISH (BISH) involves indirect detection through an enzymatic reaction. Applications in interphase cytogenetics (analysis of chromosomes in nondividing cells), viral infections, gene expression, single transcript analysis.

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