Lipomatoses.

Lipomatoses are benign proliferation of adipose tissue. Lipomas (benign fat tumors) are the most common component of lipomatosis. They may be unique or multiple, encapsulated or not, subcutaneous or sometimes visceral. In some cases, they form large areas of non-encapsulated fat hypertrophy, with a variable degree of fibrosis. They can develop despite the absence of obesity. They may be familial or acquired. At difference with lipodystrophy syndromes, they are not associated with lipoatrophy areas, except in some rare cases such as type 2 familial partial lipodystrophy syndromes (FPLD2). Their metabolic impact is variable in part depending on associated obesity. They may have functional or aesthetic consequences. Lipomatosis may be isolated, be part of a syndrome, or may be visceral. Isolated lipomatoses include multiple symmetrical lipomatosis (Madelung disease or Launois-Bensaude syndrome), familial multiple lipomatosis, the painful Dercum's disease also called Adiposis Dolorosa or Ander syndrome, mesosomatic lipomatosis also called Roch-Leri lipomatosis, familial angiolipomatosis, lipedema and hibernomas. Syndromic lipomatoses include PIK3CA-related disorders, Cowden/PTEN hamartomas-tumor syndrome, some lipodystrophy syndromes, and mitochondrial diseases, especially MERRF, multiple endocrine neoplasia type 1, neurofibromatosis type 1, Wilson disease, Pai or Haberland syndromes. Finally, visceral lipomatoses have been reported in numerous organs and sites: pancreatic, adrenal, abdominal, epidural, mediastinal, epicardial… The aim of this review is to present the main types of lipomatosis and their physiopathological component, when it is known.

Lipomatous Metaplasia Is Associated With Ventricular Tachycardia Recurrence Following Ablation in Patients With Nonischemic Cardiomyopathy.

BACKGROUND: Ventricular tachycardia (VT) recurrence rates remain high following ablation among patients with nonischemic cardiomyopathy (NICM). OBJECTIVES: This study sought to define the prevalence of lipomatous metaplasia (LM) in patients with NICM and VT and its association with postablation VT recurrence. METHODS: From patients who had ablation of left ventricular VT, we retrospectively identified 113 consecutive NICM patients with preprocedural contrast-enhanced cardiac computed tomography (CECT), from which LM was segmented. Nested within this cohort were 62 patients that prospectively underwent CECT and cardiac magnetic resonance from which myocardial border zone and dense late gadolinium enhancement (LGE) were segmented. A control arm of 30 NICM patients without VT with CECT was identified. RESULTS: LM was identified among 57% of control patients without VT vs 83% of patients without VT recurrence and 100% of patients with VT recurrence following ablation. In multivariable analyses, LM extent was the only independent predictor of VT recurrence, with an adjusted HR per 1-g LM increase of 1.1 (P < 0.001). Patients with LM extent ≥2.5 g had 4.9-fold higher hazard of VT recurrence than those with LM <2.5 g (P < 0.001). In the nested cohort with 32 VT recurrences, LM extent was independently associated with VT recurrence after adjustment for border zone and LGE extent (HR per 1 g increase: 1.1; P = 0.036). CONCLUSIONS: Myocardial LM is prevalent in patients with NICM of a variety of etiologies, and its extent is associated with postablation VT recurrence independent of the degree of fibrosis.

Mediastinal Lipomatosis.

Mediastinal lipomatosis is a benign condition characterized by excessive deposition of unencapsulated mature adipose tissue in the mediastinum.1 The exact prevalence is not known. The available literature mainly consists of some case series and a bunch of case reports.

Two cases of congenital lipomatosis in calves.

Fetal tumours in domestic animals are considered rare. Congenital lipomatous changes have been sporadically reported in fetal, neonatal and young bovids. Their prognosis is often guarded compared with benign lipocytic tumours and depends on their location and degree of infiltration. They can infiltrate the subcutis, deeper musculature and even the skeleton. Four cases of congenital infiltrative lipomatosis have been described in bovine fetuses and young calves. In this report we describe an additional two cases in a neonatal Belgian Blue White calf and a fetal dairy calf. A potential role in bovine abortion needs further investigation. Furthermore, a suggestion is made to adapt the nomenclature from infiltrative lipoma to lipomatosis in order to emphasize the poor prognosis due to the local infiltrative behaviour of these lesions.

Incomplete sensorimotor paresis after upper abdominal surgery with TEA and spinal epidural lipomatosis: a case report.

INTRODUCTION: This case report documents a postoperative, incomplete sensorimotor paraparesis from thoracic vertebral body 6 (Th6) after combined anesthesia for upper abdominal surgery in a patient who had a thoracic localization of spinal epidural lipomatosis (SEL). CASE PRESENTATION: The patient was treated in our clinic with a thoracic epidural catheter (TEA) for perioperative analgesia during a partial duodenopancreatectomy. Paraparetic symptoms occurred 20 hours after surgery. Initial MRI did not show bleeding, infection or spinal cord damage and the neurosurgeon consultants recommended observation. The neurological examination and the third follow-up MRI on 15th postoperative day showed ventrolateral damage of the spinal cord at level Th6. It is possible that local anesthetic compressed the spinal cord in addition to the existing lipomatosis and the thoracic kyphosis. The paraparesis improved during follow-up paraplegiologic treatment. CONCLUSION: So far, only two uncomplicated lumbar epidural catheter anesthesias have been described in patients who had a lumbar SEL. Epidural catheter anesthesia is a safe and effective method of pain control. But it is important to carefully identify and stratify patients with risk factors during the premedication visit. In patients who had kyphosis and thoracic localization of SEL, TEA may only be used after a risk-benefit assessment.

Synovial Lipomatosis With Extra-articular Extension in the Arthritic Wrist: An Unexpected Diagnosis.

ABSTRACT: Synovial lipomatosis is a rare condition characterized by adipocyte proliferation within joint synovial tissue. It most commonly affects the knee and is typically intra-articular. Only 5 published case reports describe extra-articular synovial lipomatosis of the wrist. We present a case of a sexagenarian patient seen for his wrist arthropathy. His x-ray revealed pan-wrist arthritis and inflammatory soft tissue swelling. The patient was slated for a wrist fusion and Darrach procedure. Following the dorsal skin incision in the operating room, an unusual adipose mass was identified infiltrating all extensor compartments: midcarpal, radiocarpal, and distal radioulnar joints. The mass was excised and sent to pathology prior to proceeding with the slated surgery. Synovial lipomatosis was diagnosed postoperatively based on histopathology. Six weeks postoperatively, the wrist fusion had healed clinically and radiographically, and his pain had improved. There was no evidence of recurrence. Synovial lipomatosis is a rare entity that may imitate multiple other pathologies. It is possible that synovial lipomatosis may represent a secondary occurrence following degenerative articular disease or trauma in older patients. This is the first case report to date describing synovial lipomatosis of the wrist with extra-articular extension in the setting of pan-carpal wrist arthritis.

Role of epidural fat in the local milieu: what we know and what we don't.

PURPOSE: Traditionally, the epidural fat (EF) is known as a physical buffer for the dural sac against the force and a lubricant facilitating the relative motion of the latter on the osseous spine. Along with the development of the studies on EF, controversies still exist on vital questions, such as the underlying mechanism of the spinal epidural lipomatosis. Meanwhile, the scattered and fragmented researches hinder the global insight into the seemingly dispensable tissue. METHODS: Herein, we reviewed literature on the EF and its derivatives to elucidate the dynamic change and complex function of EF in the local milieu, especially at the pathophysiological conditions. We start with an introduction to EF and the current pathogenic landscape, emphasizing the interlink between the EF and adjacent structures. We generally categorize the major pathological changes of the EF into hypertrophy, atrophy, and inflammation. RESULTS AND CONCLUSIONS: It is acknowledged that not only the EF (or its cellular components) may be influenced by various endogenic/exogenic and focal/systematic stimuli, but the adjacent structures can also in turn be affected by the EF, which may be a hidden pathogenic clue for specific spinal disease. Meanwhile, the unrevealed sections, which are also the directions the future research, are proposed according to the objective result and rational inference. Further effort should be taken to reveal the underlying mechanism and develop novel therapeutic pathways for the relevant diseases.

Encephalocraniocutaneous Lipomatosis: A Case Report.

ABSTRACT: Encephalocraniocutaneous lipomatosis (ECCL) is a rare congenital syndrome and subclassification of oculoectodermal syndrome. Encephalocraniocutaneous lipomatosis may be associated with postzygotic mutations. However, absence of an identifiable mutation does not preclude a diagnosis of ECCL. Encephalocraniocutaneous lipomatosis commonly causes skin, eye, and central nervous system anomalies. Diagnosis can be made through genetic sequencing or standardized clinical criteria. One clinically apparent major criterion for the diagnosis of ECCL is nevus psiloliparus (NP), a fatty nevus with overlying nonscarring alopecia. In this case, a 50-day-old female infant with uncomplicated birth history presented to dermatology clinic for evaluation of 2 superficial cranial masses that had been present since birth without regression or evolution. One of the masses was located within the hairline and demonstrated overlying nonscarring alopecia, suspicious of NP. Because of concern for ECCL, brain magnetic resonance imaging was ordered and revealed 2 intracranial lipomas. Genetic testing was inconclusive. Excision of the masses was performed at the request of the parents for cosmetic purposes. Histologic evaluation of the surgical specimens confirmed the diagnosis of NP and ECCL. A suspected NP should raise concern for ECCL and prompt further evaluation for systemic involvement. In particular, patients with suspected ECCL should be screened for ocular and CNS involvement. Early identification and diagnosis are important for prognostication because patients with ECCL are at increased risk of developing neoplasms of the head and neck and may require more frequent screening examinations.

A 58-Year-Old Woman with Acute Torsion of the Small Bowel Due to Diffuse Intestinal Lipomatosis.

BACKGROUND Diffuse intestinal lipomatosis is a rare condition that infiltrates mature fatty tissue into the intestinal submucosa and subserosa of the small or large intestine and can present with intestinal obstruction or torsion. This report is of the case of a 58-year-old woman who had acute torsion of the small bowel due to diffuse small intestinal lipomatosis. CASE REPORT A 58-year-old woman, who was otherwise in good health, arrived at our Emergency Department experiencing sudden, intense pain in the lower abdomen. She also reported abdominal swelling, feelings of nausea, vomiting, and reduced ability to defecate for at least 2 days. The next morning, contrast-enhanced abdominal computed tomography (CT) scan was performed, showing diffuse thickening of the small intestinal wall with hypodensity, fatty density, lumen narrowing, and wall thinning. The small intestine demonstrated a whirlpool-like distribution in the lower right abdomen and localized thickening of the small intestinal wall, suggesting acute intestinal torsion. An hour later, an emergency operation was performed to remove part of the small intestine. Three days later, pathological results showed a thin intestinal wall, expansion of the mucosal layer and submucosa, and hyperplasia of adipose tissue. CONCLUSIONS This report presents a rare case of torsion and small bowel obstruction caused by diffuse intestinal lipomatosis and focuses on the abdominal enhanced CT scan, which showed diffuse thickening of the small intestine, with multiple areas of fat density and torsion of the small intestine in the right lower abdomen. Histopathology is also presented, with the result showing intestinal lipomatosis.

Clinical, imaging, and pathological characteristics of congenital infiltrating lipomatosis of the face.

Congenital infiltrating lipomatosis of the face (CILF) is a rare congenital disease of the head and neck region. In this study, the cases of 20 patients diagnosed with CILF were reviewed retrospectively to analyse the characteristics of the disease. The symptoms, signs, and clinical progression were investigated. Radiological changes were analysed according to the distribution of the trigeminal nerve. The pathological features of the fatty facial lesions, jaw hyperplasia, and lingual lesions were further identified. All 20 patients demonstrated hemifacial hypertrophy at birth. None had a family history of the disease. Significant radiological features of CILF (prevalence ≥90%) included thickened buccal subcutaneous fat, palatal submucosal fat, and temporal subcutaneous fat, maxillary tuberosity heteroplasia, and fatty infiltration of the masseteric intermuscular space. With regard to the trigeminal nerve, the frontal branch region (CNV1) was rarely affected, while the maxillary (CNV2) and mandibular (CNV3) branch regions showed considerable changes. Pathologically, CILF was observed to be characterized by the infiltration of mature adipose tissue into the adjacent buccal soft tissue, osteal remodelling surrounded by sheets of mature lipocytes and supporting fibrovascular stroma, and lingual hamartoma. In summary, CILF exhibits distinct characteristics that are related to the regions controlled by the maxillary and mandibular branches of the trigeminal nerve, suggesting that CILF may be associated with early neural development.

Calcified Sclero-Choroidal Choristomas in Mosaic RASopathies: A Description of a New Imaging Sign.

PURPOSE: To evaluate the imaging and clinical features of unusual calcified lesions seen in the fundus of patients with mosaic RASopathy. DESIGN: Single-center retrospective observational study. SUBJECTS: Ten eyes with calcified fundus lesions in 7 patients with mosaic RASopathy. METHODS: The lesions were evaluated with fundus photography, oral fundus fluorescein angiography, B-scan ultrasonography, magnetic resonance imaging (MRI), and computed tomography (CT) scan where available. MAIN OUTCOME MEASURES: The imaging characteristics of calcified fundus lesions were assessed. RESULTS: We found 7 patients with mosaic RASopathies, 5 men and 2 women (3 with linear sebaceous nevus syndrome, 3 with oculoectodermal syndrome, and 1 with encephalocraniocutaneous lipomatosis) with molecular confirmation in 5 cases, all 5 having KRAS-pathogenic variants. Calcified fundus lesions were identified in 10 eyes (bilateral in 3 patients), appearing as slightly elevated, creamy-yellow lesions around or adjacent to the optic nerve, extending supero-nasally; all but 2 of these lesions involved both the choroid and sclera, with 2 of them only involving the sclera at the time of examination. One case developed a choroidal neovascular membrane necessitating intravitreal bevacizumab injections. All 7 patients had B-scan ultrasonography, and the lesion appeared as a hyperechogenic area with an acoustic shadow posteriorly despite reduced gain. Five patients had MRI, and where fundus lesions were present, there was a focal defect in the sclero-choroidal layer. Four patients had a CT scan, and all 4 showed calcifications affecting both the posteromedial sclero-choroid and adjacent medial rectus muscle. Two of these patients had normal eye movements, 1 had a unilateral fixed adducted eye and a vestigial fibrous medial rectus muscle seen in imaging and intraoperatively, and the fourth had marked exotropia with a right gaze deficit affecting both eyes. CONCLUSIONS: We propose that the lesions seen in this cohort are calcified sclero-choroidal choristomas and should be suspected in mosaic RASopathies when creamy-yellow lesions are seen in the fundus. If identified, the possibility of choroidal neovascularization should be considered during follow-up. In all cases where a CT scan was performed, a novel sign of sclero-muscular calcification involving the medial rectus muscle was seen. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Clinical characteristics and surgical management of facial infiltrating lipomatosis: a single center experience.

BACKGROUND: Facial infiltrating lipomatosis (FIL) is a rare condition characterized by congenital facial enlargement. Beyond its impact on physical appearance, FIL can also impair essential facial functions such as swallowing, chewing, vision, and breathing, imposing a substantial physiological and psychological burden. Currently, fewer than 80 cases of FIL have been reported, and the characteristics and management strategies for FIL remain unclear. METHODS: We reviewed the clinical, surgical, and radiological records of 39 FIL patients who were treated at our center. Of these, genetic testing was performed for 21 patients. RESULTS: Aberrant overgrowth involves subcutaneous fat, bones, muscles, glands, tongue, lips, and teeth. Epidermal nevi could be observed in the dermatomes innervated by the three branches of the trigeminal nerve, with the highest frequency seen in the dermatome of the mandibular branch. Four patients exhibited concurrent hemimegalencephaly (HMEG), with one case presenting HMEG on the opposite side of the FIL. Nineteen patients were confirmed to harbor the PIK3CA mutation. Thirty-three patients underwent surgical procedures, with a post resection recurrence rate of approximately 25%. CONCLUSIONS: A variety of maxillofacial structures may be involved in FIL. PIK3CA mutations are important pathogenic factors. Emerging targeted therapies could present an additional treatment avenue in the future. However, surgery currently remains the predominant treatment choice for FIL. The timing and modality of surgery should be individually customized, taking into account each patient's unique circumstances. Notably, there is a significant possibility of postoperative recurrence during childhood and adolescence, necessitating early strategic planning of disease management.

Adipocytes in synovial fluid cytology: An approach for diagnosing synovial lipomatosis.

A 2-year-old neutered male bullmastiff dog was presented with chronic left hind limb lameness. Physical examination revealed left stifle effusion and medial buttress without cranial tibial thrust. Radiographs showed joint effusion and new bone formation at the patella apex. Magnetic resonance imaging showed increased synovial fluid, widening of the joint space, abnormal infrapatellar fat body and thinning of the cranial cruciate ligament. Synoviocentesis and cytologic evaluation of synovial fluid revealed marked mononuclear inflammation with abundant fatty tissue, suggesting synovial lipomatosis in conjunction with the imaging findings. The disease was confirmed histologically after sampling the lesion during arthrotomy. Synovial lipomatosis, characterized by extensive synovial adipose tissue proliferation of the synovial membrane, is a rare "tumor-like" disorder that usually affects the stifle. Although the etiology remains unclear, joint trauma, inflammation, instability, and lipid abnormalities have been proposed as causes. Inflammatory factors may promote synoviocyte and adipocyte hyperplasia that perpetuate the process. Surgical removal may be suggested to eliminate triggers and prevent future recurrences. The report provides the first cytological description of adipocytes in synovial fluid associated with the diagnosis of synovial lipomatosis in dogs. This case report underscores the potential effectiveness of cytologic analysis of synovial fluid smears, in combination with magnetic resonance imaging (MRI), for diagnosing this condition and reducing complications associated with arthrotomy for sampling purposes. Additionally, the case highlights that synovial lipomatosis should be considered as a potential differential diagnosis for synovial masses in dogs. Further cases are needed to validate these observations in veterinary medicine.

Navigating the complexities of encephalocraniocutaneous lipomatosis: a case series and review.

INTRODUCTION: Encephalocraniocutaneous lipomatosis (ECCL) is a rare congenital syndrome with complex skin, eye, and central nervous system (CNS) symptoms. Diagnosis and treatment are challenging due to its rarity and diverse manifestations. It often involves issues like porencephalic cysts, cortical atrophy, and low-grade gliomas in the CNS, resulting in developmental delays. The spinal cord is frequently affected, leading to problems like medullary compression and radiculopathy, causing back pain and sensory/motor deficits. Surgical interventions are reserved for symptomatic cases to address hydrocephalus or alleviate spinal lipomas. This article reviews a case series to assess surgical risks and neurological outcomes. CASE SERIES: We present a case series ECCL, focusing on the diffuse lipomatosis of the spinal cord and the intricate surgical procedures involved. A multi-stage surgical approach was adopted, with continuous neuromonitoring employed to safeguard motor pathways. We discuss clinical characteristics, imaging studies, and indications for neurosurgical interventions. DISCUSSION: ECCL is a complex syndrome. Diagnosis is challenging and includes clinical evaluation, neuroimaging, and genetic testing. Treatment targets specific symptoms, often requiring surgery for issues like lipomas or cerebral cysts. Surgery involves laminectomies, spinal fusion, and motor pathway monitoring. Thorough follow-up is crucial due to potential CNS complications like low-grade gliomas. Hydrocephalus occurs in some cases, with endoscopic third ventriculostomy (ETV) preferred over ventriculoperitoneal shunt placement. CONCLUSION: Neurosurgery for ECCL is for symptomatic cases. ETV is preferred for hydrocephalus, while the treatment for lipoma is based on the presence of symptoms; the follow-up should assess growth and prevent deformities.

Expression and Significance of Inflammatory Factors in Idiopathic Spinal Epidural Lipomatosis (Grade III).

BACKGROUND: Idiopathic spinal epidural lipomatosis (iSEL) is frequently associated with the utilization of steroids, endocrine disorders, obesity, and surgical interventions. Nevertheless, the pathogenesis of iSEL remains inadequately understood. The study aimed to investigate the contribution of inflammatory factors to idiopathic epidural lipomatosis. METHODS: Thirteen patients with iSEL (Grade III, iSEL group) and 12 patients with lumbar disc herniation (control group) who underwent unilateral biportal endoscopy from March 2020 to April 2023 were enrolled. Histological examination of adipose tissue was the performed to analyze expressions of pro-inflammatory cytokines (TNF-α, IL-1ß), and anti-inflammatory factors (arginase-1, IL-10) in serum and epidural adipose cells. RESULTS: Compared with the control group, the number of inflammatory cell infiltrations per field in HE-stained sections was significantly elevated, TNF-α and IL-1ß expression in adipocytes of epidural adipose tissue were markedly higher, and arginase-1 and IL-10 expression were significantly lower in the iSEL group (all p < 0.001). However, no statistically significant differences were observed in the serum level of TNF-α, IL-1ß, arginase-1, and IL-10 between the two groups (p = 0.963). In addition, there was also no significant disparity in adipocyte size between the two groups (p = 0.739). CONCLUSION: iSEL demonstrated elevated inflammatory cells and imbalance towards proinflammatory cytokines in adipocytes of epidural adipose tissue that may be associated with the pathogenesis of symptomatic iSEL. These data suggest that inflammatory response could be one of the mechanisms of iSEL. However, further multicenter epidemiological investigations and rigorous basic and clinical research are warranted to elucidate the specific etiology of iSEL.

Next generation sequencing aids diagnosis and management in a case of encephalocraniocutaneous lipomatosis.

Encephalocraniocutaneous lipomatosis (ECCL) is a rare neurocutaneous disorder caused by somatic FGFR1 and KRAS variants. It shares significant phenotypic overlap with several closely related disorders caused by mutations in the RAS-MAPK pathway (mosaic RASopathies). We report a diagnostically challenging case of ECCL in which next-generation sequencing of affected tissue identified a pathologic FGFR1 p.K656E variant, thereby establishing a molecular diagnosis. Patients with FGFR1-associated ECCL carry a risk of developing malignant brain tumors; thus, genetic testing of patients with suspected ECCL has important management implications.