Background Atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) is the most controversial category of the Bethesda System. The present study was conducted to compare the histological findings in a series of thyroid nodules diagnosed with AUS/FLUS after single or repeat fine needle aspiration (FNA) cytology. Methods Retrospective analysis of our institution's series of 514 patients with an initial diagnosis of AUS/FLUS between 11/2011 and 02/2020. Results Of 4887 FNA samples, 11.8% were classified as AUS/FLUS. Of patients with an initial AUS/FLUS diagnosis, 11.5% (59/514) underwent surgery after a single FNA, 55.4% (285/514) had a repeat FNA, and 32.7% (168/514) were either observed or lost to follow‐up. Surgical pathology was available in 123 cases (23.9%), and malignancy was confirmed in 32.5% (40/123) cases, with similar rates in the single 32.2% (19/59) and repeat FNA 32.8% (21/64) groups. Repeat FNA reclassified 78.9% of the AUS/FLUS cases to a different category: 57.2% were reclassified as benign, 10.5% as follicular neoplasm, and 5.6% as suspicious for malignancy or malignant. The rates of nonneoplastic benign lesions were 52.5% (31/59) and 31.2% (20/64) in the single and repeat FNA groups, respectively (P = .018). The rates of follicular adenomas were higher when repeat FNA was performed (23/64, 35.9%) compared with a single FNA (9/59; 15.2%) (P = .013). Conclusion In this series, a repeat FNA in cases of AUS/FLUS increased detection of follicular adenomas but not the detection of malignancy. Repeat FNA reduced the rate of benign nonneoplastic lesions by 40% in the surgical samples.

The prevalence of different types of clear cells and of the mite Demodex in the nipple-areola complex of adult autopsies of both sexes not suffering from breast cancer was studied in a total of 140 nipples. The epidermis of the nipple-areola complex shows squamous cells and 3 types of clear cells: Toker cells, pagetoid dyskeratosis cells, and signet ring-like cells. Toker cells were identified by standard light microscopy in 13 of 140 nipples (9.3%). Reactivity of these cells for CK7 was observed in 35 nipples (25%). They are derived from the lactiferous duct epithelium. Pagetoid dyskeratosis cells were identified in 56 of 140 nipples (40%). In 12 nipples, these cells were conspicuous (8.6%). It is suggested that the proliferation of these cells is induced by friction. Signet ring-like cells were identified in 71 nipples (50.7%). In 2 nipples, these cells were conspicuous (1.4%). They are a consequence of artefact related to formalin fixation. The prevalence of all these clear cells has no relationship with gender. Routine histopathological examination is usually enough to distinguish the characteristic features of the clear cells involving the nipple epidermis and permits differentiation of other entities with epidermal pale cells. Demodex mites were observed in 58 nipple-areola complexes (41.4%). They were more common in male nipple-areola complexes (P < 0.05). The prevalence of these mites was seen to remain steady along the years since the third decade. Demodex mites are common parasites of human nipple and are apparently of no pathologic significance.

Mineral oil has been frequently used in most of high voltage transformers. However, this oil has started to be replaced by vegetable oils. Additionally, different authors have found that mineral oil-based nanofluids have a potential in improving insulating properties of transformer oil. In order to improve the characteristics of a commercial vegetal oil, this work has used TiO2 nanoparticles to obtain a nanofluid whose ageing behavior at 150ºC for 300 hours has been studied.

Lymphangioma is a rare benign lesion of the gastrointestinal tract, in which the large intestine is the least commonly involved site. To the authors' knowledge a lymphangioma of the anal canal has not been reported. Described herein is a case of pedunculated polypoid lymphangioma of the right lateral wall on the transitional zone of the anal canal measuring 1.7 x 1.3 x 1 cm in a 40-year-old woman. A pedicle does not exclude the endoscopic diagnosis of lymphangioma. Lymphangioma must be included in the differential diagnosis of polypoid lesions of the anal canal.