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Pathology of Breast Cancer
Published in Raymond Taillefer, Iraj Khalkhali, Alan D. Waxman, Hans J. Biersack, Radionuclide Imaging of the Breast, 2021
Attempts have been made to utilize ancillary studies to distinguish between atypical ductal hyperplasia and DCIS. We have observed that immunostaining for muscle-specific actin highlights the myoepithelial cells in atypical ductal hyper plasia and can be used as a useful diagnostic adjunct [73-75]. Our experience and others' reported in the literature, however, have concluded that other ancillary studies such as the study of HER-2/neu oncogene expression, DNA ploidy and/or nuclear measurements do not provide or substantiate evidence to differentiate between atypical hyperplasia and carcinoma [76-79]. Thus, until we design a long-term prospective study monitoring the natural history of atypical hyperplasias and ductal carcinoma in situ, the unresolved diagnostic issues will continue and create confusion for the patients, pathologists, and clinicians.
Actions of Dopamine on the Skin and the Skeleton
Published in Nira Ben-Jonathan, Dopamine, 2020
As shown in Figure 11.8 and is detailed in Table 11.1, the skin has two types of sweat glands. One type are the apocrine sweat glands, which secrete fluid into the sac of the hair follicle through which it comes out on the skin. The other type are the eccrine sweat glands, which secrete sweat directly onto the surface of the skin. Accordingly, apocrine glands are located deep in the layers of the skin while eccrine glands are more superficially placed. Sweat glands are composed of an intraepidermal spiral duct, a dermal duct made of a straight and a coiled portion, and a secretory tubule, coiled deep in the dermis or hypodermis. The coiled portion is formed by two concentric layer of columnar or cuboidal epithelial cells. The epithelial cells are interposed by myoepithelial cells that support the secretory epithelial cells. The duct of the gland is formed by two layers of cuboidal epithelium and open through the sweat pore. The secretory part of the apocrine glands is larger than that of eccrine glands.
Skin and Organs with Epidermoid Mucosae
Published in George W. Casarett, Radiation Histopathology, 2019
The ordinary sweat glands, merocrine in character, are simple, coiled, tubular glands, with the mass of the secretory portion located in the dermis and with narrow, unbranched excretory ducts passing through the epidermis. Resting on the thick basement membrane of the secretory portion are spindle-shaped myoepithelial cells which are thought to aid in the discharge of secretion by contracting. Forming a single layer on the myoepithelial cells are truncated pyramidal cells which excrete the sweat. The epithelial cells of the secretory and duct portions of the sweat glands are relatively specialized cells with numerous mitochondria; these are reverting postmitotic cells and are relatively radioresistant, more resistant that the germinal cells of the sebaceous glands.
Myoepithelioma of bone: ultrastructural, immunohistochemical and molecular study of three cases
Published in Ultrastructural Pathology, 2019
Paweł Kurzawa, Martin K. Selig, Patryk Kraiński, Michał Dopierała, G. Petur Nielsen
Myoepithelial tumors are neoplasms that are composed exclusively or predominantly of myoepithelial cells. Neoplastic myoepithelial tumor cells resemble the non-luminal, neoplastic myoepithelial cells of pleomorphic adenomas.13 Ultrastructurally, myoepithelial cells of salivary glands are situated between secretory cells and basal lamina in ductal structures.33 By electron microscopy, each myoepithelial cell is characterized by several branching processes with their number and thickness varying from gland to gland.34 Although projections were also observed by Franchi et al. in primary juxtacortical/mixed tumors of the bone11, unfortunately, Alberghini et al.31 did not comment on their presence when describing malignant myoepithelioma of the bone. In our study, the cytoplasmic processes were retained by the neoplastic myoepithelial cells in all the cases. Interestingly, in case 1 (benign myoepithelioma) the cells had long slender processes that did not intertwine which was present in cases 2 and 3 (malignant myoepithelioma) where the cells had blunt, intertwining cytoplasmic processes. These features also help to differentiate myoepithelial cells from smooth muscle cells that lack such cytoplasmic processes.34
Physiology of sweat gland function: The roles of sweating and sweat composition in human health
Published in Temperature, 2019
The anatomical structure of the eccrine sweat gland, illustrated in Figure 2, consists of a secretory coil and duct made up of a simple tubular epithelium. The secretory tubule is continuous with and tightly coiled with the proximal duct. The distal segment of the duct is relatively straight and connects with the acrosyringium in the epidermis [5]. The secretory coil has three types of cells: clear, dark, and myoepithelial. As shown in Figure 2(c), clear cells are responsible for the secretion of primary sweat, which is nearly isotonic with blood plasma [6–8]. The clear cells contain a system of intercellular canaliculi, glycogen, and a large amount of mitochondria and Na-K-ATPase activity [5]. The dark cells are distinguishable by the abundance of dark cell granules in the cytoplasm. Their function is poorly understood, but thought to potentially act as a repository for various bioactive materials involved in regulation of clear cell and duct cell function [9,10]. The function of the myoepithelial cells is provision of structural support for the gland against the hydrostatic pressure generated during sweat production [5]. The duct has two cell layers: basal and luminal cells. Its primary function is reabsorption of Na and Cl ions as sweat flows through the duct, as shown in Figure 2(d). Most of the NaCl reabsorption occurs in the proximal duct, as these cells contain more mitochondria and Na-K-ATPase activity than that of the distal segment of the eccrine duct [5]. The result is a hypotonic final sweat excreted onto the skin surface [6,9].
An unexpected tumour of the finger: review and management
Published in Case Reports in Plastic Surgery and Hand Surgery, 2019
N. Jumper, E. Caffrey, N. McInerney
One month following referral, the patient underwent excision biopsy of the lesion which was not found to be communicating with bone, nerve or tendon and the intra-operative impression was that of a ganglion cyst (Figure 2). The initial histopathology examination reported a circumscribed multinodular predominantly solid tumour (Figure 3(a,b)) ulcerating the overlying epidermis. There were focal papillary projections with tubular/ductal structures (Figure 3(c)) where ducts were lined by a double layer of epithelium consisting of inner cuboidal cells and an outer myoepithelial layer (Figure 3(d,e,f,g)). There was also evidence of lymphovascular invasion (Figure 3(h,i)), focally high mitotic activity (Figure 3(j)) and the tumour was shown to abut the margins. Immunohistochemistry was performed (Table 1) confirming a myoepithelial cell population expressing smooth muscle actin, calponin, D2-40 (Figure 3(i)) and p63 (Figure 3(f)). The tumour was classified as digital papillary adenocarcinoma. The histopathology sections were sent to an external institution for expert opinion and the diagnosis affirmed with recommendation of complete excision and close follow-up. This recommendation was echoed when the case was discussed at the local multi-disciplinary meeting.