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Endocrine Glands
Published in Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard, Toxicologic Pathology, 2018
Richard A. Peterson, Sundeep Chandra, Mark J. Hoenerhoff
Because of its close proximity to the aortic sac during development, accessory thyroid tissue may be observed within the ventral neck along the midline or in the mediastinum (Capen and Martin 1989b). These embryonic rests are composed of normal-appearing follicles that retain hormonal function but are devoid of C-cells. In dogs, presence of this accessory tissue is quite common, and up to 50% of dogs have ectopic thyroid remnants, which have been associated with neoplastic transformation in this species. Ectopic thymus, composed of clusters of normal lymphoid tissue with typical cortical and medullary regions, may also be observed within or in close proximity to the thyroid gland (Hardisty and Boorman 1990). Thyroid cysts may occur in all species, most commonly in rats and dogs, and may be lined by either keratinizing or nonkeratinizing squamous epithelium (ultimobranchial) or cuboidal to columnar and occasionally ciliated epithelial cells (thyroglossal duct) (Capen et al. 2002). Cysts arising from the ultimobranchial bodies (ultimobranchial cysts) are located centrally within the thyroid, are lined by attenuated squamous epithelium, and contain cellular debris. The less common thyroglossal duct cyst occurs in the cranioventral neck along the ventral midline, as a result of persistence of a segment of the thyroglossal duct that is retained during development. Thyroglossal duct cysts may give rise to papillary carcinomas in dogs (Capen and Martin 1989a).
Deaths of the Young and Elderly
Published in John M. Wayne, Cynthia A. Schandl, S. Erin Presnell, Forensic Pathology Review, 2017
John M. Wayne, Cynthia A. Schandl, S. Erin Presnell
Answer B is correct. DiGeorge syndrome, also known as velocardiofacial syndrome or 22q11.2 deletion syndrome, demonstrates a constellation of features that often includes thymic hypoplasia or aplasia and cardiac defects that range in severity from asymptomatic (small aortic coarctation) to emergent (tetralogy of Fallot). The neonate may present with hypocalcemia as the parathyroid glands may also be abnormal. Other midline abnormalities such as cleft palate may result in feeding difficulties. DiGeorge syndrome may be detected by chromosomal microarray studies and usually also by FISH analysis with deletion of one 22q11.2 probe signal; however, a normal FISH analysis does not exclude DiGeorge syndrome, which is a compendium of clinical findings. Since many individuals with DiGeorge syndrome can be sufficiently managed medically and surgically, the case described is also worrisome for neglect, which should be investigated along with studies to demonstrate the suspected genetic abnormality. Note also that an ectopic thymus gland may be present, but not found by autopsy, so additional evidence for the syndrome should be present before making this diagnosis (such as genetic evidence).
Spindle Epithelial Tumor with Thymus-Like Differentiation (SETTLE): A Case Report
Published in Fetal and Pediatric Pathology, 2019
Cyrus L Matheson, Geoffrey K Blair, Jonathan Bush
Spindle epithelial tumor with thymus-like differentiation (SETTLE) is a biphasic thyroid tumor thought to arise from ectopic thymus or branchial pouch remnants, which was first characterized by Chan and Rosai [1]. Subsequently, there have been 46 reported cases of SETTLE tumors in the published literature, and only a small subset [14] with cytologic description reported [2,3]. SETTLE is a low-grade malignant tumor that occurs mostly in the pediatric and young adult patient population [1–5]. It has also been shown to have late metastatic potential; a very recent report presents a metastatic latency of 35 years in the lung [2,4–6]. The typical presentation of SETTLE is a slow-growing, painless neck mass with normal thyroid function studies. Ultrasound studies usually show a mixed solid-cystic lesion that is cold on thyroid scinti-scanning [2,5,7]. Due to the paucity of SETTLE reports, a formal workup and treatment algorithm has yet to be proposed. We report a SETTLE in an 8-year-old female with fine-needle aspirate biopsy initially suspicious for spindle-cell variant of medullary carcinoma of the thyroid. The patient and family consented to publishing this case report.
Report of a case of necrotizing autoimmune myopathy with thymoma-associated myasthenia gravis
Published in International Journal of Neuroscience, 2020
Gang Huang, Xinhua Zhou, Dongyuan Yao
Our patient had subclinical MG without any MG-related symptoms before thymectomy. After the surgery, the patient developed MG-related symptoms. This phenomenon is not uncommon. Nakajima et al. [4] reported 23% thymoma patients with AChR-Ab in serum developed symptoms of MG after thymectomy. In addition, Sun et al. [11] also found that 4 of their 6 thymoma patients were AChR-Ab positive, and all of the AChR-Ab positive patients developed MG after thymectomy. It has been reported [4] that the incidence of MG in patients with thymoma was 0.9% to 20%, and that the preoperative increase in AChR-Ab in thymoma patients was a significant risk factor in development of postoperative MG, and that AChR-Ab would increase further postoperatively [12]. The preoperative serum AChR-Ab titer had a positive predictive value of 23%, a negative predictive value of 95%, and a sensitivity of 60%, and a specificity of 80% for MG after thymectomy [4]. However, the cause of development of MG symptoms after thymectomy is unclear. Nevertheless, some studies showed that it might be due to recurrence of thymoma postoperatively [13] or ectopic thymus tissues [12]. The thymoma with serum AchR-Ab positive, B1/B2/B3 thymoma, and incomplete thymoma resection are considered to be risk factors for development of MG after thymectomy [14], which is consistent with the findings of increased preoperative AChR-Ab and type B2 thymoma in the patient in the current case report. In addition, bronchiectasis was found in the patient by chest CT examination. It might be a rare complication of thymoma, which may be associated with hypogammaglobulinemia, abnormal immune attacks and repeated recurrent coughs [15].