A macrophage-collagen fragment axis mediates subcutaneous adipose tissue remodeling in mice.

Efficient removal of fibrillar collagen is essential for adaptive subcutaneous adipose tissue (SAT) expansion that protects against ectopic lipid deposition during weight gain. Here, we used mice to further define the mechanism for this collagenolytic process. We show that loss of collagen type-1 (CT1) and increased CT1-fragment levels in expanding SAT are associated with proliferation of resident M2-like macrophages that display increased CD206-mediated engagement in collagen endocytosis compared to chow-fed controls. Blockage of CD206 during acute high-fat diet-induced weight gain leads to SAT CT1-fragment accumulation associated with elevated inflammation and fibrosis markers. Moreover, these SAT macrophages' engagement in collagen endocytosis is diminished in obesity associated with elevated levels collagen fragments that are too short to assemble into triple helices. We show that such short fragments provoke M2-macrophage proliferation and fibroinflammatory changes in fibroblasts. In conclusion, our data delineate the importance of a macrophage-collagen fragment axis in physiological SAT expansion. Therapeutic targeting of this process may be a means to prevent pathological adipose tissue remodeling, which in turn may reduce the risk for obesity-related metabolic disorders.

Sonographic comparison of subcutaneous fat layer thickness in the scalp area in patients with androgenetic alopecia compared to healthy individuals: Cross-sectional.

INTRODUCTION: Androgenetic alopecia (AGA) is one of the most common alopecia among men and women worldwide. It is a nonscarring alopecia that has a characterized pattern. In female pattern AGA, the hairline is stable but general thinning occurs most notably in the frontal region. In male-pattern AGA, the hairline is receding and the thinning is most notable in the frontotemporal region. AGA has a complex pathogenesis and relation of subcutaneous fat in the scalp region and the miniaturization of terminal hair follicles is vague. In this study, subcutaneous fat in the frontal scalp an important region for AGA is compared to the occipital scalp that is spared in AGA. METHOD: Our study is a cross-sectional study that has four groups. Male patient, female patient, male control, female control. Every group has 15 individuals. All of the people in the study are those referred to Rasoul Akram's dermatology clinic. The severity of alopecia is classified by Norwood scaling for male pattern AGA and Ludwig scaling for female pattern AGA. Subcutaneous tissue in the frontal and occipital regions is measured by ultrasonography. For evaluating the effect of aging on subcutaneous fat thickness, we subdivided any group into more than 40 years old and between 20 and 40 years old and compared these two subgroups. RESULTS: The mean age of the three groups of male patient, female patient, and female control is 40 y/o and the mean age of male control is 41 y/o. The mean subcutaneous fat layer thickness in frontal region in male patients group is 6.0 mm (more than 40 y/o = 6.6 mm, between 20 and 40 y/o = 5.5 mm), in female patients group 5.1 mm (more than 40 y/o = 5.7 mm, between 20 and 40 y/o = 4.6 mm), in the male control group is 4.4 mm (more than 40 y/o = 4.7 mm, between 20 and 40 y/o = 4 mm) and in the female control group is 4.1 mm (more than 40 y/o = 4.5 mm, between 20 and 40 y/o = 3.6 mm). The mean subcutaneous fat layer thickness in the occipital region in the male patient's group is 6.4 mm (more than 40 y/o = 6.7 mm, between 20 and 40 y/o = 6 mm), in the female patient's group 6.1 mm (more than 40 y/o = 6.5 mm, between 20 and 40 y/o = 5.7 mm), in the male control group is 6.3 mm (more than 40 y/o = 6.8 mm, between 20 and 40 y/o = 5.7 mm) and in the female control group is 6.2 mm (more than 40 y/o = 6.6 mm, between 20 and 40 y/o = 5.8 mm). CONCLUSION: This study demonstrates that the subcutaneous fat layer in the frontal region in both males and females is thicker in AGA patients than healthy group and the more severe the AGA, the thicker is subcutaneous layer in the frontal region. In the male patients group, the subcutaneous fat layer in the frontal region is thicker than in the female patients group but in the male and female control groups is not so different. The subcutaneous fat layer in the occipital region is thicker in older individuals in both patients and control groups but is not different when compared to AGA patients and control individuals.

Idiopathic calcinosis cutis in an infant: The importance of a wait-and-see approach.

A healthy 2-year-old girl presented with multiple asymptomatic subcutaneous nodules on both legs. Histologically demonstrated calcium deposition within the dermis and subcutaneous tissue consistent with calcinosis cutis. Laboratory abnormalities, underlying genetic conditions, and potential triggering factors were ruled out. The lesions resolved over an 18-month period without treatment, emphasizing the importance of the wait-and-see approach in idiopathic cases of calcinosis cutis.

Congenital liquified subcutaneous fat necrosis in a newborn: an unusual case.

Subcutaneous fat necrosis of the newborn is a self-limited disorder of the panniculus that arises in the first six weeks of life. Some differential diagnoses may be difficult such as bacterial cellulitis or erysipelas. The prognosis is usually favorable but there are serious complications for which the patient must be regularly monitored, especially hypercalcemia. We report a case of a full-term newborn with a liquidated area of subcutaneous fat necrosis. A surgical incision was performed because of the discomfort and the lack of regression. Hypercalcemia and nephrocalcinosis appeared afterward. A set of clinical, biological, and histological arguments allows the diagnosis of subcutaneous fat necrosis. Follow-up to early detection and to manage such complications is necessary.

Associations between weight change, knee subcutaneous fat and cartilage thickness in overweight and obese individuals: 4-Year data from the osteoarthritis initiative.

OBJECTIVE: To assess (i) the impact of changes in body weight on changes in joint-adjacent subcutaneous fat (SCF) and cartilage thickness over 4 years and (ii) the relation between changes in joint-adjacent SCF and knee cartilage thickness. DESIGN: Individuals from the Osteoarthritis Initiative (total=399) with > 10% weight gain (n=100) and > 10% weight loss (n=100) over 4 years were compared to a matched control cohort with less than 3% change in weight (n=199). 3.0T Magnetic Resonance Imaging (MRI) of the right knee was performed at baseline and after 4 years to quantify joint-adjacent SCF and cartilage thickness. Linear regression models were used to evaluate the associations between the (i) weight change group and 4-year changes in both knee SCF and cartilage thickness, and (ii) 4-year changes in knee SCF and in cartilage thickness. Analyses were adjusted for age, sex, baseline body mass index (BMI), tibial diameter (and weight change group in analysis (ii)). RESULTS: Individuals who lost weight over 4-years had significantly less joint-adjacent SCF (beta range, medial/lateral joint sides: 2.2-4.2 mm, p < 0.001) than controls; individuals who gained weight had significantly greater joint-adjacent SCF than controls (beta range: -1.4 to -3.9 mm, p < 0.001). No statistically significant associations were found between weight change and cartilage thickness change. However, increases in joint-adjacent SCF over 4 years were significantly associated with decreases in cartilage thickness (p = 0.04). CONCLUSIONS: Weight change was associated with joint-adjacent SCF, but not with change in cartilage thickness. However, 4-year increases in joint-adjacent SCF were associated with decreases in cartilage thickness independent of baseline BMI and weight change group.

Common Histological Features Suggesting Enchondral Ossification Pathways in Calciphylaxis of Various Origins: A Study of Human Subcutaneous Tissue Biopsies.

Calciphylaxis is a rare, yet underdiagnosed condition causing high mortality in patients with severe renal and cardiovascular disease. Since knowledge of the pathophysiology of calciphylaxis is limited, a differential analysis of histological alterations in patient subgroups with various comorbidities might expose different disease phenotypes and allow deeper insights into the pathophysiology of the condition. Histological markers of osteogenesis and calcification were investigated in a group of 18 patients with clinically and histologically verified calciphylaxis, using immunohistochemical staining. Analysis of staining intensity and distribution of marker proteins in histological structures was performed to evaluate distinct patterns between subgroups with different clinical comorbidities in comparison with a control group. In all cases, immunohistochemical staining for bone matrix proteins, bone-morphogenic proteins and matrix-Gla proteins co-localized with subcutaneous vascular and interstitial calcifications. Significant expression of bone-morphogenic protein-7 and active matrix-Gla protein was observed. Mortality was associated with renal comorbidities and increased expression of bone-morphogenic protein-7. However, no distinct histological patterns were found between subgroups with renal disease, warfarin intake or coexisting micro- and macro-angiopathies. The upregulation of osteogenic markers (including bone-morphogenic protein-7) plays a major role in the development of calciphylaxis. Clinical outcome correlates with kidney function and phosphate handling, suggesting different pathophysiological mechanisms. However, biopsy  at late-stage disease shows a common histological phenotype, involving enchondral ossification.

Subcutaneous fat infiltration into the dermal layer induces wrinkle formation.

BACKGROUND: Wrinkles appear with aging, producing an aged impression, but the mechanism of wrinkle formation has not yet been fully elucidated. We recently reported that subcutaneous fat infiltrates into the dermal layer with aging and impairs skin elasticity, but the contribution of this process to wrinkle formation is still unclear. PURPOSE: We aimed to clarify the contribution of dermal fat infiltration to wrinkle formation by analyzing the relationship between them in the forehead of female volunteers. METHODS: We measured the severity of fat infiltration in the forehead of 29 middle-aged female volunteers by means of ultrasonography. Fixed wrinkles present when the eyes were closed and wrinkles transiently formed when the eyes were open were evaluated using a photograph-based 6-grade evaluation system for each type of wrinkle. RESULTS: Fat infiltration at the forehead area was observed similarly to that in the cheek area as we reported previously. We found that opening the eyes induced the formation of stable transient wrinkles, the grade of which was significantly related to fat infiltration severity. Furthermore, fat infiltration was also significantly related to the severity of fixed wrinkles. Moreover, the severity of transient wrinkles was significantly related to that of fixed wrinkles. CONCLUSIONS: Our results suggest that fat infiltration into the dermal layer enhances transient wrinkle formation during facial expression by impairing the ability of the skin to resist deformation, thereby promoting fixed wrinkle formation. Therefore, fat infiltration is a critical cause of wrinkle formation.

Electrochemical lipolysis of subcutaneous adipose tissue in a porcine animal model.

OBJECTIVES: There is a considerable demand for noninvasive low-cost fat reduction methods with fewer side effects and shorter recovery times. This study aims to develop a fat-reduction method through electrochemical lipolysis of subcutaneous adipocytes using needle-based electrodes, body tissue fluids, and electrical current application. METHODS: Electrochemical lipolysis was performed by inserting a 4-pin needle electrode connected to a DC power supply into the pig's abdomen. Applied electrical current (0.5 and 1 mA) and treatment time (5 or 10 minutes) were varied systematically. Ultrasound imaging was performed before and after treatment to determine changes in fat thickness. Tissue samples were collected at 0, 2, and 4 weeks posttreatment for histological evaluation to determine the mechanism of action and the procedure's efficacy. RESULTS: Electrochemical subcutaneous adipose tissue lipolysis in a porcine model was achieved through hydrolysis of physiologic fluid within the vicinity of the inserted electrode where an electric current is applied, leading to localized disruption of fat cell membranes and necrosis. Electric current configuration 1.0 mA showed more pronounced lipolysis effects applied for 10 minutes, significantly decreasing adipocyte content per treatment area. The electrochemical treatment method also stimulates collagen synthesis, which helps reduce fat. CONCLUSIONS: Electrochemical lipolysis is a potential new noninvasive localized technique to reduce fat. The treatment method induces fat cell necrosis via in situ reduction-oxidation reaction by the electrochemical activation of physiologic fluid in the surrounding tissue. Electrochemical lipolysis is a simple, low-cost, fat-reducing treatment method without harmful side effects.

Rapid cytologic diagnosis of subcutaneous fat necrosis of the newborn.

Subcutaneous fat necrosis of the newborn is a rare self-limited panniculitis that classically presents within the first few weeks of life. The diagnosis is typically clinical, but some cases require skin biopsy with hematoxylin and eosin stain for confirmation. We report a previously undocumented rapid diagnostic protocol that involves collecting a small amount of exudate from a suppurative lesion, placement onto a slide without fixation, and simply viewing the material under a microscope. This novel and practical method of diagnosis reveals doubly refractile crystals diagnostic of subcutaneous fat necrosis without a biopsy, which may be helpful for rapid diagnosis or use in low resource settings.

Secondary diffuse large B-cell breast lymphoma developed in subcutaneous fat layer of the breast with cardiac involvement.

We present a rare case of diffuse large B-cell lymphoma developed in subcutaneous fat layer of the breast with cardiac involvement. Radiologists should perform an image-guided biopsy for pathologic confirmation of breast lymphomas and avoidance of unnecessary invasive treatment.

Obesity activates immunomodulating properties of mesenchymal stem cells in adipose tissue with differences between localizations.

Mesenchymal stem cells from healthy adipose tissue are adipocytes progenitors with immunosuppressive potential that are used for years in cell therapy. Whether adipose stem cells (ASC) may prevent inflammation in early obesity is not known. To address this question, we performed a kinetic study of high-fat (HF) diet induced obesity in mice to follow the immune regulating functions of adipose stem cells (ASC) isolated from the subcutaneous (SAT) and the visceral adipose tissue (VAT). Our results show that, early in obesity and before inflammation was detected, HF diet durably and differently activated ASC from SAT and VAT. Subcutaneous ASC from HF-fed mice strongly inhibited the proliferation of activated T lymphocytes, whereas visceral ASC selectively inhibited TNFα expression by macrophages and simultaneously released higher concentrations of IL6. These depot specific differences may contribute to the low-grade inflammation that develops with obesity in VAT while inflammation in SAT is delayed. The mechanisms involved differ from those already described for naïve cells activation with inflammatory cytokines and probably engaged metabolic activation. These results evidence that adipose stem cells are metabolic sensors acquiring an obesity-primed immunocompetent state in answer to depot-specific intrinsic features with overnutrition, placing these cells ahead of inflammation in the local dialog with immune cells.

Responsiveness of Subcutaneous Fat, Intermuscular Fat, and Muscle Anatomical Cross-Sectional Area of the Thigh to Longitudinal Body Weight Loss and Gain: Data from the Osteoarthritis Initiative (OAI).

Thigh subcutaneous (SCF) and intermuscular (IMF) fat have been associated with joint health and function. Here, we explore the (sex-specific) responsiveness of SCF, IMF, and muscle during longitudinal weight loss and gain, as well as the change in questionnaire-based and physical performance-based knee function measures. This exploratory study included 103 Osteoarthritis Initiative (OAI) participants, who displayed a ≥10% weight loss or gain between baseline (BL) and 2-year (Y2) follow-up (and maintained half of that weight loss until year 4) and had axial 3T magnetic resonance images (MRI) for measuring SCF, IMF, and muscle cross sectional areas (CSAs). The standardized response mean (SRM = mean divided by the standard deviation of the change) was used as a measure of responsiveness. A total of 52 OAI participants (73% women) displayed ≥10% weight loss, and 51 (67% women) ≥10% weight gain. Both SCF and IMF CSAs showed a significant decrease (mean change) with weight loss (SCF: -22%, SRM = -1.2; IMF: -15%, SRM = -0.7) and a significant increase with weight gain (SCF: +27%, SRM = 1.1; IMF: +21%, SRM = 0.6). Muscle CSAs showed significant changes during weight loss (extensor: -8.3%, SRM = -1.1; flexor: -7.2%, SRM = -1.0), but not during weight gain. Knee function measures were not relevantly associated with bidirectional changes in body weight. SCF and IMF CSAs are highly responsive to bidirectional weight change, whereas muscle CSAs were only responsive to weight loss. These findings highlight that MRI represents a sensitive tool for monitoring changes in thigh adipose tissue composition that may be applied during specific diet and/or exercise interventions.

Pcpe2, a Novel Extracellular Matrix Protein, Regulates Adipocyte SR-BI-Mediated High-Density Lipoprotein Uptake.

Objective: To investigate the role of adipocyte Pcpe2 (procollagen C-endopeptidase enhancer 2) in SR-BI (scavenger receptor class BI)-mediated HDL-C (high-density lipoprotein cholesterol) uptake and contributions to adipose lipid storage. Approach and Results: Pcpe2, a glycoprotein devoid of intrinsic proteolytic activity, is believed to participate in extracellular protein-protein interactions, supporting SR-BI- mediated HDL-C uptake. In published studies, Pcpe2 deficiency increased the development of atherosclerosis by reducing SR-BI-mediated HDL-C catabolism, but the biological impact of this deficiency on adipocyte SR-BI-mediated HDL-C uptake is unknown. Differentiated cells from Ldlr-/-/Pcpe2-/- (Pcpe2-/-) mouse adipose tissue showed elevated SR-BI protein levels, but significantly reduced HDL-C uptake compared to Ldlr-/- (control) adipose tissue. SR-BI-mediated HDL-C uptake was restored by preincubation of cells with exogenous Pcpe2. In diet-fed mice lacking Pcpe2, significant reductions in visceral, subcutaneous, and brown adipose tissue mass were observed, despite elevations in plasma triglyceride and cholesterol concentrations. Significant positive correlations exist between adipose mass and Pcpe2 expression in both mice and humans. Conclusions: Overall, these findings reveal a novel and unexpected function for Pcpe2 in modulating SR-BI expression and function as it relates to adipose tissue expansion and cholesterol balance in both mice and humans.

Visceral-to-subcutaneous fat ratio exhibits strongest association with early post-operative outcomes in patients undergoing surgery for advanced rectal cancer.

AIM: Despite their promise as prognostic factors in colorectal cancer, anthropometric data are frequently contradictory or difficult to interpret, with single body-composition parameters often investigated in isolation or heterogeneous clinical cohorts used in analyses. We sought to assess a spectrum of body-composition parameters in a highly selected cohort with locally advanced rectal cancer in a bid to determine those with strongest prognostic potential in this specific setting. MATERIALS/METHODS: Between 2014 and 2020, 78 individuals received neoadjuvant chemotherapy, or chemoradiotherapy, followed by radical surgery in the treatment of locally advanced rectal adenocarcinoma at Oxford University Hospitals Trust. Demographic, treatment-related, perioperative, and short-term outcomes data were assessed. Body-composition parameters included BMI, and those derived from pre-operative computed-tomography imaging: skeletal mass index (SMI), visceral fat area (VFA), subcutaneous fat area (SFA), perinephric fat area (PFA) visceral-to-subcutaneous fat ratio (V/S), sarcopenia, and sarcopenic obesity (SO). RESULTS: Pre-operative body-composition parameters exhibited particularly strong correlation with post-operative outcomes, with VFA (p = 0.002), V/S (p = 0.019), SO (p = 0.012), and PFA (p = 0.0016) all associated with an increased length of hospital stay. Univariate and multivariate analyses demonstrated V/S to be the sole independent body-composition risk factor to be associated with an increased risk of developing Clavien-Dindo complications ≥ 2 (p = 0.033) as well as an increased length of stay (p = 0.005). CONCLUSION: Among patients with locally advanced rectal cancer, high visceral-to-subcutaneous fat ratio is the body-composition parameter most strongly associated with poor early post-operative outcomes. This should be considered in patient selection and prehabilitation protocols. WHAT DOES THIS PAPER ADD TO THE LITERATURE? : Our study demonstrates that among body composition parameters, high visceral-to-subcutaneous fat ratio is strongly associated with increased risk of post-operative complications and increased length of stay in patients undergoing surgery for advanced rectal cancer.

Visceral Adipose Tissue Inflammation and Radiographic Visceral-to-Subcutaneous Adipose Tissue Ratio in Patients with Cirrhosis.

BACKGROUND AND AIMS: Accumulation of visceral adipose tissue is associated with hepatic inflammation and fibrosis, suggestive of its metabolic and inflammatory properties. We aimed to examine the histologic findings of visceral and subcutaneous adipose tissue and to associate these findings with clinical and radiologic characteristics in patients with cirrhosis. METHODS: Included were 55 adults with cirrhosis who underwent liver transplantation from 3/2017-12/2018 and had an abdominal computed tomography (CT) scan within 6 months prior to transplant. Visceral-to-subcutaneous adipose tissue ratio (VSR) was calculated using visceral (VATI) and subcutaneous adipose tissue index (SATI) quantified by CT at the L3-vertebral level and normalized for height (cm2/m2). VAT (greater omentum), SAT (abdominal wall), and skeletal muscle (rectus abdominis) biopsies were collected at transplant. RESULTS: Majority of patients had VAT inflammation (71%); only one patient (2%) had SAT inflammation. Patients with VAT inflammation had similar median VATI (42 vs 41 cm2/m2), lower median SATI (64 vs 97 cm2/m2), and higher median VSR (0.63 vs 0.37, p = 0.002) than patients without inflammation. In univariable logistic regression, VSR was associated with VAT inflammation (OR 1.47, 95%CI 1.11-1.96); this association remained significant even after adjusting for age, sex, BMI, HCC, or MELD-Na on bivariable analyses. CONCLUSION: In patients with cirrhosis undergoing liver transplantation, histologic VAT inflammation was common, but SAT inflammation was not. Increased VSR was independently associated with VAT inflammation. Given the emerging data demonstrating the prognostic value of VSR, our findings support the value of CT-quantified VSR as a prognostic marker for adverse outcomes in the liver transplant setting.

Anti-adipogenic signals at the onset of obesity-related inflammation in white adipose tissue.

Chronic inflammation that affects primarily metabolic organs, such as white adipose tissue (WAT), is considered as a major cause of human obesity-associated co-morbidities. However, the molecular mechanisms initiating this inflammation in WAT are poorly understood. By combining transcriptomics, ChIP-seq and modeling approaches, we studied the global early and late responses to a high-fat diet (HFD) in visceral (vWAT) and subcutaneous (scWAT) AT, the first being more prone to obesity-induced inflammation. HFD rapidly triggers proliferation of adipocyte precursors within vWAT. However, concomitant antiadipogenic signals limit vWAT hyperplastic expansion by interfering with the differentiation of proliferating adipocyte precursors. Conversely, in scWAT, residing beige adipocytes lose their oxidizing properties and allow storage of excessive fatty acids. This phase is followed by tissue hyperplastic growth and increased angiogenic signals, which further enable scWAT expansion without generating inflammation. Our data indicate that scWAT and vWAT differential ability to modulate adipocyte number and differentiation in response to obesogenic stimuli has a crucial impact on the different susceptibility to obesity-related inflammation of these adipose tissue depots.

Genetic and cytometric analyses of subcutaneous adipose tissue in patients with hemophilia and HIV-associated lipodystrophy.

BACKGROUND: The authors recently performed plastic surgeries for a small number of patients with hemophilia, HIV infection, and morphologic evidence of lipodystrophy. Because the pathophysiological mechanism of HIV-associated lipodystrophy remains to be elucidated, we analyzed subcutaneous adipose tissues from the patients. METHODS: All six patients had previously been treated with older nucleoside analogue reverse-transcriptase inhibitors (NRTIs; stavudine, didanosine or zidovudine). Abdominal and inguinal subcutaneous fat samples were obtained from the HIV+ patients with hemophilia and HIV- healthy volunteers (n = 6 per group), and analyzed via DNA microarray, real-time PCR, flow cytometry and immunohistochemistry. RESULTS: The time from initial NRTI treatment to collecting samples were 21.7 years in average. Cytometric analysis revealed infiltration of inflammatory M1 macrophages into HIV-infected adipose tissue and depletion of adipose-derived stem cells, possibly due to exhaustion following sustained adipocyte death. Genetic analysis revealed that adipose tissue from HIV+ group had increased immune activation, mitochondrial toxicity, chronic inflammation, progressive fibrosis and adipocyte dysfunction (e.g. insulin resistance, inhibited adipocyte differentiation and accelerated apoptosis). Of note, both triglyceride synthesis and lipolysis were inhibited in adipose tissue from patients with HIV. CONCLUSIONS: Our findings provide important insights into the pathogenesis of HIV-associated lipodystrophy, suggesting that fat redistribution may critically depend on adipocytes' sensitivity to drug-induced mitochondrial toxicity, which may lead either to atrophy or metabolic complications.

Infiltration of subcutaneous adipose layer into the dermal layer with aging.

BACKGROUND: The elasticity of the dermal layer decreases with aging, leading to ulcer formation and wrinkling, but the mechanism of this change is not fully understood, because it is difficult to access the complex three-dimensional (3D) internal structure of the dermis. OBJECTIVE: To clarify age-dependent changes in the overall 3D structure of the dermal layer by means of 3D analysis technology. METHODS: We observed sun-protected human skin by means of X-ray micro CT, identified the layers of the skin, and reconstructed the 3D structure on computer. Age-dependent structural changes of the dermal layer were evaluated by statistical comparison of young and aged skin. RESULTS: Histological observations suggested the presence of two types of ectopic fat deposits, namely infiltrated subcutaneous fat and isolated fat, in the lower region of the reticular dermal layer in aged skin. To elucidate their nature, we observed skin specimens by X-ray microCT. The epidermis, dermal layer, and subcutaneous adipose layer were well differentiated on CT images, and 3D skin was digitally reconstructed on computer. This method clearly showed that the isolated fat observed histologically was in fact connected to the subcutaneous fat, namely all ectopic fat is connected to the subcutaneous adipose layer. Statistical analysis showed that the severity of fat infiltration into dermal layer is significantly increased in aged skin compared with young skin. CONCLUSION: Our findings indicate that subcutaneous fat infiltrates into the dermal layer of aged skin. Our 3D analysis approach is advantageous to understand changes of complex internal skin structures with aging.

Utility of high-resolution ultrasound in measuring subcutaneous fat thickness.

OBJECTIVE: Previous studies conclude that high-resolution ultrasound (HRUS) enables noninvasive and accurate measurements of subcutaneous fat thickness. The primary objective of this cross-sectional study was to better characterize subcutaneous fat thickness measurements in a diverse patient population using HRUS. Secondarily, we sought to correlate these measurements with patients' body image. METHODS: A cross-sectional study to measure subcutaneous fat measurements at seven distinct anatomic sites, including upper and lower extremities, submental, and torso regions, in 40 men and women of different ages and races using HRUS. Independent t-tests and analysis of variance were performed to analyze findings. RESULTS: In our patient population, on average, women had thicker subcutaneous fat than men at all anatomic sites. Asian patients had significantly reduced fat thickness at peripheral anatomic sites, such as arms when compared to patients who identified as Black and Other (p = 0.05 and p = 0.008, respectively). Lastly, women reported decreased total body satisfaction at all anatomic sites when compared to men. CONCLUSION: The information obtained and methods developed in this study may be utilized clinically during patient selection for fat reduction procedures, including for estimating the degree of likely benefit; for managing pathologies involving subcutaneous fat thickness alteration; and to monitor the progression of lipodystrophy secondary to disease or drugs.

Atypical fibroxanthoma and pleomorphic dermal sarcoma: Is superficial infiltration in subcutaneous tissue acceptable in AFX?

BACKGROUND: Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are rare cutaneous neoplasms forming a spectrum. Case reports with recurrences and metastasis have been published despite the current view that AFX is benign. The aim of this study was to identify clinical and histopathological features that predict tumor recurrence. METHODS: A retrospective review of AFX and PDS cases was performed. Clinical characteristics were obtained from patient records. RESULTS: A total of 29 AFX and 23 PDS cases were identified. Review led to re-classification of 12 cases (18%). In 14/50 (26.9%) cases a recurrence occurred. Recurrences were significantly more likely to occur when the tumor showed any infiltration in the subcutaneous fat (100% vs 43.2%, p = 0.000) or when the tumor diameter exceeded 2 cm (46.2% vs 16.2%, p = 0.030). CONCLUSIONS: This study shows that histopathological distinction between AFX and PDS remains difficult with reclassification in 12 out of 52 (18%) cases upon review. All AFX cases solely confined to the dermis behaved benign. We therefore advocate to classify all cases with any form of subcutaneous extension as PDS, and only lesions without as AFX. This contrasts with the current general opinion in which superficial subcutaneous invasion is still accepted in AFX.