Fat cells and membranous fat necrosis of aortic valves: a clinicopathological study.

We examined 152 aortic valves (AVs), which included 82 postmortem non-dysfunctional AVs (nd-AVs) and 70 surgically removed dysfunctional AVs showing aortic stenosis (AS), aortic regurgitation (AR), or combined AS and AR (AS-R). Fat cells, membranous fat necrosis (MFN), and fat-MFN-related lesions composed of fat cells and/or MFN were found in 127 (83.6%), 110 (72.4%), and 140 (92.1%) of 152 AVs, respectively, and all were associated with older age (P = 0.010, P = 0.022, and P = 0.003, respectively). MFN was associated with fibrous thickening and calcification (both, P = 0.001). Nd-AV fat cells and fat-MFN-related lesions were not correlated with body mass index. Compared with age- and sex-matched control cases, MFN in AS and AS-R cases was more frequent (P = 0.030 and P = 0.045, respectively), but MFN in AR cases showed no significant differences. Fat-MFN-related lesions, possibly representing true preceding fat cells, showed no differences in AVs with and without dysfunction or in dysfunctional types. These data suggest that AV fat cells are age-related, obesity-independent, and AV dysfunction-unrelated common phenomenon. MFN is also age-dependent and could be caused by AS and AS-R, which is probably concerned with AV thickening and calcification.

Membranous fat necrosis of gall bladder, a case report and literature review.

INTRODUCTION AND IMPORTANCE: Membranous fat necrosis is a rare histological finding. Despite its low incidence and lack of clinical significance, it can involve various organs. Majority of membranous fat necrosis cases are diagnosed in breast lumps and skin in comparison to intra-abdominal lesions. There has been only one reported case of membranous fat necrosis of gall bladder in literature. CASE PRESENTATION: A 56-year-old female patient with previous history of diabetes mellitus and hypertension was administered due to abdominal pain and fever. Based on her physical exam, lab data, and ultrasonography, she was diagnosed by cholangitis. After primary care, she went under cholecystectomy. The histological finding of gall bladder revealed crenulated fatty membranes phagocytized by macrophages in Hematoxylin and Eosin (H&E) staining. Moreover, necrosis and giant cells were seen on Sudan black staining. Hence, the diagnosis of membranous fat necrosis in gall bladder was made. CLINICAL DISCUSSION: Membranous fat necrosis occurs when peripheral blood circulation is compromised. Ischemia of fat tissue cause fatty membranous material accumulation acting as foreign bodies. Hence, it can attract inflammatory response. Regarding pathology, phagocyted membranous by macrophages and giant cells is diagnostic. Sudan black, Luxol fast blue (LFB), long Ziehl-Neelsen, and D-PAS are positive in membranous fat necrosis. CONCLUSION: Membranous fat necrosis of gall bladder is a rare entity. This is the second reported case of such diagnosis. Nonetheless, further pathological investigations are necessary.

Lipomembranous fat necrosis: A distinctive and unique morphology (Review).

Lipomembranous fat necrosis (LFN) is an uncommon but distinct form of fat necrosis, which is characterized by eosinophilic, crenulated and/or serpiginous membranes. LFN exhibits macrocystic, microcystic and/or crushed features. LFN is routinely detectable on hematoxylin and eosin (H&E)-stained sections, and is present both in the acute phase and in the later or fibrous stage of necrotic fatty lesions. Smaller crushed LFN embedded within fibrous tissues may be difficult to recognize on H&E-stained sections, but can be highlighted by some staining techniques, including Masson trichrome, periodic acid-Schiff, orcein, long Ziehl-Neelsen stain, silver impregnation, phosphotungstic acid-hematoxylin and luxol fast blue staining. LFN was initially considered a specific feature of Nasu-Hakola disease, but has since been identified in various subcutaneous or intraabdominal lesions related to ischemic conditions or venous insufficiency. In addition, LFN is detectable in intra-articular loose bodies and aortic valves with or without dysfunction, suggesting that LFN is also associated with ischemia-like hypoxic conditions or malnutrition. LFN is considered to be a histological hallmark of hidden ischemic or hypoxic/malnourished conditions in various diseases; however, the exact mechanisms of LFN remain poorly understood. The present review described the clinicopathological features of this interesting, but poorly characterized, condition.

Adipocytes and membranous fat necrosis within native cardiac valves: Clinicopathologic characterization of histologic constituents.

The constituents of normal cardiac valves as well as those involved by active and/or chronic processes have been detailed previously, however minor attention has been provided toward mature adipocytes within valves and correlation with other histologic, clinical, and echocardiographic data. The literature also contains a paucity of investigations examining the presence of a particular form of degenerative change of mature adipocytes termed membranous fat necrosis. We retrospectively reviewed the histologic findings of 1042 native cardiac valves which included identification of the presence of adipocytes and membranous fat necrosis within them, as well as correlation with other histopathologic features, and clinical and echocardiographic findings. Notable observations included that membranous fat necrosis was only present in valves with adipocytes, adipocytes and membranous fat necrosis were seen in older patients, and that Caucasians made up a greater proportion of patients while African Americans made up a lower proportion of patients when valves were found with adipocytes and membranous fat necrosis. Aortic valves contained adipocytes and membranous fat necrosis at a greater rate than compared to other valves, and aortic valves with adipocytes and membranous fat necrosis were more commonly tricuspid (as opposed to bicuspid) and with larger aortic valve area and lower peak and mean gradients. Further investigation is required to determine potential physiologic and/or pathologic consequence of their presence.

Intraductal membranous fat necrosis in a fibroadenoma of breast: a case report.

Membranous fat necrosis is an unusual type of fat necrosis occurring in the breast and normally involves the parenchyma. This report describes an apparently unique intraductal focus in a fibroadenoma following prior needling. Displacement of fatty tissue in the form of membranous fat necrosis within ducts could be added to the list of histological features following core biopsy.

A Case of Lipoma with Membranous Fat Necrosis / 대한피부과학회지

Membranous fat necrosis is a variant of fat necrosis characterized by the presence of membranocystic foci which is lined by eosinophilic, homogeneous and crenulated membrane that has pseudopapillary projections. Membranous fat necrosis may be idiopathic or has been associated with many local and systemic diseases. The pathogenesis of membranous fat necrosis is uncertain but trauma may be suspected in our case. We describe a case of lipoma with membranous fat necrosis.

A Case of Membranous Fat Necrosis with Calcification in Lipoma / 대한피부과학회지

Membranous fat necrosis, an uncommon disorder, was first described by Nasu et al. in 1973. This is characterized by the presence of membranocystic foci in which cysts are lined by an eosinophilic homogeneous membrane with pseudo papillary luminal projections. We, herein, report a case of membranous fat necrosis with calcification in lipoma which developed on the abdomen of a 47-year-old woman. To our knowlege, this is the first report on membranous fat necrosis with calcification in lipoma, in Korea.