Benign Lipoma Research Articles

Liposarcoma of the scalp mimicking a lipoma: a case report

BackgroundLiposarcomas are malignant tumours of adipocytic differentiation and their occurrence within the head and neck region is very uncommon. Lipomas are the most common types of benign mesenchymal tumours. The clinical, histological and imaging features of well-differentiated liposarcoma may resemble that of lipoma, causing challenges in the diagnosis. The management and prognosis of benign lipomas and well-differentiated liposarcoma are different.Case presentationA 73-year-old man presented with a painless soft mass in the left temporal region for 15 years with recent rapid growth. The scalp mass was clinically diagnosed as lipoma, while MRI suspected an atypical lipomatous lesion. Complete surgical resection was performed, and histopathological examination confirmed a well-differentiated liposarcoma.The patient recovered completely and will be followed up with long-term surveillance.ConclusionThis report is to highlight that clinicians must have a high index of suspicion for this rare entity when dealing with scalp masses and suspicious radiological findings, which can affect the overall management and prognosis.

Orbital intramuscular lipoma with bone erosion

This report highlights a rare case of a benign orbital intramuscular lipoma mimicking a malignant tumor with unusual sphenoid wing destruction. A 2-year-old female patient presented with proptosis of the left eye, left temporal fullness, and motility disturbance during abduction. Brain and orbital computed tomography revealed an inhomogeneous enhancing density partially circumscribed mass in the left extraconal space (36.6 × 34.4 × 34.2 mm) with bone erosion of the greater wing of the left sphenoid bone. The clinical and radiologic findings suggested rhabdomyosarcoma. Histopathology revealed diffuse infiltration of mature adipocytes in the striated muscle. An intramuscular lipoma, a rare subtype of benign lipoma, can mimic malignant orbital tumors due to adjacent bone erosion.

Characterization of lipomatous tumors with high-resolution 1H MRS at 17.6T: Do benign lipomas, atypical lipomatous tumors and liposarcomas have a distinct metabolic signature?

BackgroundDistinguishing between some benign lipomas (BLs), atypical lipomatous tumors (ALTs), and dedifferentiated liposarcomas (DDLs) can be challenging due to overlapping magnetic resonance imaging characteristics, and poorly understood molecular mechanisms underlying the malignant transformation of liposarcomas.PurposeTo identify metabolic biomarkers of the lipomatous tumor spectrum by examining human tissue specimens using high-resolution 1H magnetic resonance spectroscopy (MRS).Materials and methodsIn this prospective study, human tissue specimens were obtained from participants who underwent surgical resection for radiologically-indeterminate lipomatous tumors between November 2016 and May 2019. Tissue specimens were obtained from normal subcutaneous fat (n=9), BLs (n=10), ALTs (n=7) and DDLs (n=8). Extracts from specimens were examined with high-resolution MRS at 17.6T. Computational modeling of pattern recognition-based cluster analysis was utilized to identify significant differences in metabolic signatures between the lipomatous tumor types.ResultsSignificant differences between BLs and ALTs were observed for multiple metabolites, including leucine, valine, branched chain amino acids, alanine, acetate, glutamine, and formate. DDLs were distinguished from ALTs by increased glucose and lactate, and increased phosphatidylcholine. Multivariate principal component analysis showed clear clustering identifying distinct metabolic signatures of the tissue types.ConclusionMetabolic signatures identified in 1H MR spectra of lipomatous tumors provide new insights into malignant progression and metabolic targeting. The metabolic patterns identified provide the foundation of developing noninvasive MRS or PET imaging biomarkers to distinguish between BLs, ALTs, and DDLs.

MicroRNAs as Potential Biomarkers in the Differential Diagnosis of Lipomatous Tumors and Their Mimics.

Adipocytic tumors are the most common subtype of soft tissue tumors. In current clinical practice, distinguishing benign lipomas from well-differentiated liposarcomas (WDLPS), as well as dedifferentiated liposarcomas (DDLPS) from their morphologic mimics, remains a significant diagnostic challenge. This is especially so when examining small biopsy samples and without the aid of additional ancillary tests. Recognizing the important role that microRNAs (miRNAs) play in tumorigenesis and their potential utility in tumor classification, we analyzed routine clinical tissue samples of benign and malignant lipomatous tumors, as well as other sarcoma mimics, to identify distinguishing miRNA-based signatures that can aid in the differential diagnosis of these entities. We discovered a 6-miRNA signature that separated lipomas from WDLPS with high confidence (AUC of 0.963), as well as a separate 6-miRNA signature that distinguished DDLPS from their more aggressive histologic mimics (AUC of 0.740). Functional enrichment analysis unveiled possible mechanistic involvement of these predictive miRNAs in adipocytic cancer-related biological processes and pathways such as PI3K/AKT/mTOR and MAPK signaling, further supporting the relevance of these miRNAs as biomarkers for adipocytic tumors. Our results demonstrate that miRNA expression profiling may potentially be used as an adjunctive tool for the diagnosis of benign and malignant adipocytic tumors. Further validation studies are warranted.

MDM2 analysis in the management of benign lipomas versus atypical lipomatous tumors/well-differentiated liposarcomas: A useful prognostication tool?

IntroductionWell-differentiated liposarcomas (WDLS) are low-grade lipomatous tumors with low malignant potential. Previous review identified controversy on whether upfront wide resection is necessary when they occur on the trunk or the extremities. MDM2 amplification is a genetic mutation typically present in WDLS and absent in benign lipomas (BL). We aimed to study the influence of MDM2 status on the management/recurrences of lipomatous tumors in the trunk or the extremities. MethodsAll patients with lipomatous tumors with MDM2 testing in the Province of Alberta between 2015 and 2020 were identified from the Cancer Cytogenetics Laboratory dataset. High grade sarcomas, retroperitoneal, head/neck, or groin tumors were excluded. Primary outcome measures including MDM2 status, surgical margin, local recurrence, reoperation rate, dedifferentiation, and metastasis were abstracted from chart review. Descriptive statistics were used to analyse treatment patterns and recurrence rates according to MDM2 status. ResultsTotal of 764 charts were retrieved, and 282 were included for analysis. 33 showed MDM2 amplification (11.7%), and 2 of them had local recurrence (6.1%). Two patients with recurrent tumors underwent limb-salvaging reoperation (6.1%), but no dedifferentiation or metastasis was seen. ConclusionFindings in this study confirmed the benign behaviour of truncal/extremities lipomas with no MDM2 amplification. Given we found a 6.1% recurrence rate in MDM2 amplified tumors, a prolong follow up of this subset of patients is warranted. Overall, regardless of the MDM2 status, we believe an initial marginal excision is a reasonable surgical approach as recurrences are rare, and they can be managed with re-excision when they occur.

Giant Lipoma of Hand in a Child: Case Report and Literature Review

Although lipomas are the most common benign form of soft tissue tumors that are >5 cm in diameter. They are extremely rare in the hand localization. They are slowly progressive and usually do not cause numbness or weakness of the hand. They can be deceptively large and extensive leading to misdiagnosis. We present here one such case in which symptomatic swelling over sole of right hand was excised and confirmed as a benign lipoma.

Radiological manifestations of benign mesenteric lipoma that presented with acute intestinal obstruction: A case report

BackgroundIntestinal obstruction is a common surgical emergency that is presented to the hospital with various aetiologies. Among all, mesenteric lipoma is one of the uncommon extraluminal causes of intestinal obstruction. In such conditions, bowel volvulus, compression or even adhesion are the underlying pathologies.Case presentationWe report a 69-year-old gentleman who presented with a triad of intestinal obstruction which required exploratory laparotomy. Preoperative computed tomography revealed multiple coalescing lobulated hypoattenuating lesions encircling part of a small bowel forming transitional zone. These lesions are comparatively more hypoattenuating in comparison with the surrounding mesenteric fat. Intraoperatively, a giant ileal mesenteric lipoma was identified causing compression and folding to the adjacent small bowel, leading to proximal bowel dilatation. Excision of the lipoma with a few mesenteric lymphadenectomy was done, revealing a benign mesenteric lipoma and reactive lymph nodes. Despite ileus, he made a good postoperative recovery and was discharged well.ConclusionsPatients with recurrent abdominal pain must have a thorough endoscopic and imaging assessment. Besides common or malignant aetiology, rarities should be considered and actively sought. Mesenteric lipoma is a relatively indolent tumour for which early detection can alter clinical presentation.

Colocolic intussusception because of lipoma in a 44-year-old adult

Lipoma is an uncommon mesenchymal tumor of the colon. They are typically symptom free, the large lipomas within the colon are rare, and can cause obstruction, bleeding, or intussusception. Intussusception is comparatively common in pediatrics and in adults, it could be a rare entity. Pathologic lesions are usually found with a major percentage of malignancy. This is a retrospective evaluation of an adult with an intestinal intussusception who underwent oncosurgical treatment. He was diagnosed with surgically proven intussusception. Using ultrasound and colonoscopy as diagnostic studies, colocolic intussusception was discovered. The patient underwent oncosurgical exploration. Intestinal resection with abrupt anastomosis was the procedure of choice for the patient. The etiology was benign lipoma. Adult intussusception should be evaluated in any patient with subacute abdominal discomfort with bearing in mind the high rate of malignancy and a lower rate of benign tumors. intestinal resection without reducing is highly recommended for colonic intussusceptions.

An unusual case of quadruple polyorchidism in a human cadaver mimicking bilateral lipoma

Polyorchidism is a rare congenital disorder defined as the presence of more than two testicles for which the underlying etiology is unknown. This report examines a novel case, correlates findings to the literature, and discusses potential mechanisms of dysgenesis. This study was conducted on a 96-year-old male cadaver. Meticulous skilled dissection was done with careful attention to the pelvis, the inguinal region, the scrotum and testes. Measurements of the scrotal testes (STs), supernumerary testes (SNTs), scrotal epididymides (SEs), supernumerary epididymides (SNEs), ductus deferens (DD) and supernumerary ductus deferens (SDD) were taken, and testicular volume was calculated. Sagittal sectioning of STs, SNTs, SEs and SNEs was performed and, using standard histologic protocol, tissues were processed, stained with H&E, and examined. Histological findings supported the anatomical suspicion of high, bilateral inguinal polyorchdism, or tetraorchdism, in this patient. STs and SNTs have normal, gross morphological features. The left SNT was supplied by the testicular artery, and the right SNT by the inferior epigastric artery. Both SNTs and SNEs were infiltrated with adipose tissue, whereas the scrotal homologues were histologically normal. Testicular volumes were 26.5 cm3 and 23.7 cm3, and 12.3 cm3 and 0.55 cm3, for the left and right STs and SNTs, respectively. The left and right SEs measured 7.2 cm and 7.0 cm; the left and right SNEs measured 4.7 cm and 1.7 cm, respectively. The left DD measured 40.2 cm from the scrotum. The SDD from the left SNT measured 5.9 cm and joined the main ductus 16 cm proximal to its origin. The right main DD measured 39.2 cm, and the SDD from the right SNT was 3.2 cm and joined the main DD 17.4 cm proximal to its origin. The current work suggests a novel classification for polyorchidism of Type 3, Subgroup B, or SNT attached to the draining epididymis and vas deferens without reproductive potential and SNT located outside the scrotal sac. Clinicians must correlate anatomical and histological findings in suspected polyorchids to avoid misdiagnosis of SNTs as benign lipomas.

Fibrolipoma of Neck - A Case Report

Introduction: Lipoma is the most common benign mesenchymal tumor of adipose tissue. Their occurrence in the head and neck is relatively rare. Lipomas in the neck region are rare tumors that usually present as slowly growing painless masses, found in the lateral portions of the neck. Case Report: Here, we report a case of lipoma lying over the right nape of the neck in a 26-year-old female. A pedunculated overgrowth was gradually progressive in size with no other complaints. It was soft, mobile and non-tender. It was clinically diagnosed as a fibroepithelial polyp and later on, a histopathological examination was performed which revealed benign lipoma. Surgical excision is an elective treatment. However, an accurate differential diagnosis, postsurgical histological examination and careful follow-up are required. The purpose of this case report is to recognize rare lipomas that occur in unusual locations in the head and neck in order to identify them when they cause diagnostic problems. Conclusion: Lipomas can occur in any site of the body, However, rare variants in unusual sites should not be ignored by clinicians and should be sent for histopathological diagnosis for a confirmed diagnosis.

Dumbbell shaped giant intramuscular pelvic lipoma: a rare cause of sciatic nerve compression

Background: Lipoma is a common benign mesenchymal tumor that is typically located in the subcutaneous tissue and rarely symptomatic. Sciatica can be a result of various etiologies but a giant intramuscular pelvic lipoma causing sciatic nerve compression is rare, with not more than 10 cases reported so far in the literature. Case Presentation: We report a case of a 36-year-old female who presented with a complaint of gradually worsening sciatica for 6 months. Magnetic resonance imaging showed a large well-defined intramuscular dumbbell-shaped mass in the right gluteal region, herniating through the sciatic foramen into the pelvis. After successful resection of the mass transabdominally, the histopathological examination confirmed the diagnosis of a benign lipoma. The patient improved gradually thereafter and is asymptomatic since then. Conclusion: Our case not only describes the appropriate diagnosis and surgical management of this common benign entity with a rare location and even rarer clinical presentation but also creates a paradigm for future insight into the effective management of such a patient.

A Retrospective Study of Adipocytic Tumours Received at a Tertiary Care Center

Introduction: Adipocytic tumours comprise a large proportion of the vast histomorphological spectrum of soft tissue tumours. They range from benign lipomas to malignant liposarcomas with an entire range of various histological sub-types in between. Liposarcomas account for 15-20% cases of soft tissue sarcomas diagnosed. They are characterized with a high recurrence rate, progression to higher grade with time making their correct and prompt diagnosis imperative.
 Aims: To analyze the clinicopathological profile of adipocytic tumours received at a tertiary care center over a period of three years. To determine the distribution of adipocytic tumours among different age groups and gender. To ascertain the most common site of occurrence/organ involved. To determine the most common histopathological subtypes among the benign and malignant adipocytic tumours.
 Study Design: Retrospective Descriptive study.
 Place and Duration of Study: Saveetha Medical College and Hospital, between July 2017-June 2020.
 Methodology: All cases of adipocytic tumours (218) inclusive of both resection and biopsy specimens received during the study period were included and their case records were accessed. The demographic details were obtained from the case records at the Medical Records Division and the histomorphological findings from the histopathology registers at the Department of Pathology. 
 Results: In this study, from a total of 20,767 specimens received at our tertiary care center during the period of study, 1.05% (218) were adipocytic tumours, of which 97.25% (212) were benign lipomas and 2.75% (6) were malignant liposarcomas. Out of the total number of malignant tumours (1050) received during the period of study, 2.95% (31) were soft tissue sarcomas, out of which 19.35% (6) cases were liposarcomas. Among the liposarcomas received at our center, 50% (3) cases were well differentiated liposarcoma, 33.3% (2) cases were pleomorphic liposarcoma and 16.7% (1) cases were dedifferentiated liposarcoma.

Multiple symmetric and multiple familial lipomatosis

Lipomas are the most common soft tissue tumors and are malignant in only 1% of cases. Lipomatosis is defined as the presence of multiple benign lipomas on the body, without lipoatrophy. Their impact on quality of life is significant. Different entities have been described such as symmetrical multiple lipomatosis (MSL), also called Madelung's disease and familial multiple lipomatosis (FML). MSL occurs preferentially in men (but also women) who are alcohol abuser. There are different subtypes of the disease, the most classic of which affects the upper body and the nuchal region with a buffalo hump appearance. A metabolic component with obesity is frequent. In contrast to Dercum's disease, there is no pain. SAOS, complications of the metabolic syndrome and of alcohol abuse including cancers, may be associated and should be screened. FML has been little described in the literature since Brodie's first report in 1846. FML occurs preferentially in the third decade but equally in women and men. Its autosomal dominant component is classically accepted with variable penetrance within the same family. Association with naevi, angiomas, polyneuropathies and with gastrointestinal comorbidities has been reported. Interestingly, and in contrast with most lipodystrophy disorders, the patients show an insulin sensitivity profile. A better understanding of the underlying pathophysiological mechanisms would open up avenues on therapeutic research, since treatments are only symptomatic to date.

En-block resection of a giant retroperitoneal lipoma presented as huge abdominal swelling: a case report

Retroperitoneal lipomas are an extremely rare entity with only less than 20 cases described in the literature so far. They can attain immoderate size due to space provided in the retroperitoneum and cause abdominal symptoms like abdominal pain, swelling and obstipation due to mass effect. Case presented here as of 53 years old male with complaint of abdominal swelling that had been progressive for the last 1 year. On computed tomography (CT) it revealed giant retroperitoneal mass? liposarcoma? occupying the space immensely. Intraoperatively, two giant retroperitoneal tumours were found which did not show any features of infiltration to nearby structures, therefore the sole tumour annihilation was achieved, which was diagnosed as benign lipoma on histopathology report later. The most important differential diagnosis is the well differentiated liposarcoma, which could only be confirmed after resection and histopathological assessment. Retroperitoneal lipomas are clearly not distinguishable from well differentiated liposarcomas on CT guided and USG guided biopsy and thus it could be misleading. Hence surgical resection with negative margins along with histopathological confirmation is treatment of choice with regular follow up to diagnose early recurrence if any.

Review of Head and Neck Masses in the Indian Population Based on Prevalence and Etiology With an Emphasis on Primary Diagnostic Modalities.

Head and neck masses are classified as sebaceous cysts (epidermoid cysts), cervical lymphadenopathy, benign lipomas, lymph nodes, thyroid swellings, or tuberculosis lymphadenitis that may be painful or painless, adherent or fluctuant. In spite of this, they have distinct prognoses and pathological features. The anatomical location of the swelling and other demographic manifestations of the patient provide valuable information about the cause and type of swelling. Computed tomography (CT), magnetic resonance imaging, positron emission tomography-CT, and ultrasonography are the gold standard imaging methods for the head and neck examination. These methods are used according to the region considered for the study. Fine-needle aspiration cytology of lymph nodes is known to be effective, simple, and sometimes the only tool for the diagnosis of lymph node malignancies. This review highlights the epidemiological aspect of head and neck masses in the Indian population.

Posterior interosseous nerve entrapment by intramuscular lipoma arising from the supinator muscle - a case report

Abstract Background: Lipomas are benign, slow-growing tumors frequently subcutaneous and asymptomatic, intramuscular lipoma constituting a rare subtype. However, a lipoma occurring nearby the proximal radius may cause posterior interosseous nerve (PIN) entrapment. Case presentation: We described an uncommon case of a 45-year-old-man with a history of progressive, painless proximal right (dominant) forearm swelling for 4 months associated with PIN entrapment syndrome, presenting as fingers extension weakness. Intramuscular lipoma was observed in the supinator muscle in the magnetic resonance imaging (MRI). Lipoma surgical excision and release of the PIN through proximal forearm direct anterior approach was performed. Results: The histopathological examination confirmed the diagnosis of benign intramuscular lipoma. The follow-up of the patient showed full recovery within three months postoperatively. Discussion: Intramuscular lipoma is rare; however, it could originate from supinator muscle in the forearm, presenting with vague pain and could lead to compression of nearby neurovascular structures such as the PIN. Clinical evaluation and imaging studies, especially MRI, are crucial for diagnosis. If neural compression is evident, surgical resection is mandatory. Conclusion: Intramuscular lipoma entrapping PIN is rare and requires early clinical diagnosis confirmed by imaging and neurophysiological studies, surgical excision being the method of choice for optimum functional outcomes.

The incidence and relevance of non-fatty components in trunk and extremity lipomatous soft tissue masses.

To determine the incidence and diagnostic relevance of non-fatty 'solid appearing' components within lipomatous tumours of the trunk and extremity. Retrospective review of patients referred to a specialist musculoskeletal oncology service over a 12-month period with a lipomatous trunk or extremity soft tissue tumour. The presence and morphology (solitary/multifocal; homogeneous/heterogeneous; well-defined/poorly defined) of non-fatty components was recorded based on MRI and compared with the final histological diagnosis. 213 patients with 217 lipomatous tumours were included, 119 (55.9%) males and 94 (44.1%) females with mean age of 54.6 years (range 7-93 years). Seventy-seven (35.5%) lesions arose superficial to the fascia and 139 (64.1%) deep, while a single case involved both compartments. Mean maximal tumour dimension was 94.9 mm (range 12-288 mm). Non-fatty 'solid appearing' components were identified in 28 (12.9%) cases, of which eight were solitary and 20 were multifocal, six had homogeneous SI and 22 had heterogeneous SI, and eight had well-defined margins, while 20 had poorly defined margins. Histological diagnosis was available in 20 of the tumours containing non-fatty components, 16 of which were benign, two intermediate grade and two malignant (a dedifferentiated liposarcoma and a myxoid liposarcoma). The commonest diagnosis was spindle cell lipoma, which accounted for 10 of 20 (50%) cases with confirmed histology. Non-fatty components are identified in ~13% of trunk and extremity lipomatous tumours. The majority of such lesions are benign lipoma variants, most commonly spindle cell lipoma. Solid non-fatty components are identified in approximately 13% of lipomatous tumours referred to a specialist sarcoma service. Despite the concern that these may represent dedifferentiated liposarcomas, high-grade tumours were seen in only two cases, the commonest diagnosis being a spindle cell lipoma.

54. Genome-wide copy number abnormalities in lipomatous neoplasms detected with chromosomal microarray: Is gain of MDM2 necessary for 12q amplification characterization and prognostication?

Lipomatous neoplasms (LN) are a heterogeneous group of adipocytic tumors, including benign lipomas, low-grade atypical lipomatous tumors (ALT), and high-grade liposarcomas [sub-grouped into de-differentiated liposarcomas (DDLS) evolved from ALT and pleomorphic liposarcomas]. Using histological (H&E) approaches, ALT are often difficult to distinguish from benign lipomas, while DDLS are challenging to differentiate from other high-grade sarcomas. Given this diagnostic challenge, molecular signatures can aid in the characterization/prognostication of these tumors and have shown MDM2 and/or CDK4 amplification in ALT and DDLS tumors, with MDM2 being recognized as the likely “driver” gene, based on fluorescence in situ hybridization (FISH) studies. We describe an atypical lipomatous tumor having features of spindle cell lipoma. A genome-wide copy number microarray (MA) assessment showed amplification on 3q (6-10 copies; 4 contiguous regions) and 12q (6-11 copies; 7 contiguous regions), with the 12q amplification regions being juxtaposed to, but not encompassing, the MDM2 gene. A FISH test for this specimen, using a commercial probe, yielded an “MDM2” positive result (albeit with smaller signals). This “discrepant” finding is not unexpected since the 209 kb FISH probe encompasses loci other than MDM2, including the CPM gene (which is amplified in the MA). To our knowledge, this is the first documented case of 12q amplification in a LN that does not encompass the MDM2 gene. Moreover, in our experience (n= 44 tumors), 100% of the 12q (MDM2/CPM) amplified LN have shown additional imbalances using MA methods [including, but not limited to, amplifications of 1q (60%); CDK4 and/or HMGA2 (58%), & HMGA2 (25%)]. In summary, our data underscore the advantages of using MA to evaluate LN. Moreover, this rare tumor having 12q15 amplification that does not encompass the MDM2 gene may provide new insight as to the role of MDM2 (versus possibly CPM) as a “driver” for ALT/DDLS tumor formation/progression.

Recent Advancement in Atypical Lipomatous Tumor Research.

After Evans and colleagues identified the lipomatous tumor with a well-differentiated liposarcoma in a subcutaneous location or within a muscle layer, namely, atypical lipomatous tumor (ALT), this malignancy has been investigated to clarify the characteristics of clinical behavior and genomic changes. As one of the important issues for clinicians, it is a hot topic of how to distinguish ALT from benign lipoma in the clinical aspect. Recent studies revealed novel findings to clarify the risk factor for the diagnosis of ALT and molecular targets for the treatment of ALT. Clinical characteristics of superficial-type ALT well reflect the subcutaneous location of the tumor and are slightly different compared to deep-type ALT, such as tumor size. In addition, there has been a recent discovery of novel findings in ALT-related genes, namely, HMG2A (high mobility group protein 2a), YEATS4 (YEATS domain containing 4), and CPM (Carboxypeptidase M). Recent updates on treatment for advanced ALT are well developed including immunotherapy and conducting clinical trials. Finally, this review introduces one of the hot topics of ALT research focused on epigenetic changes: their attention in recent updates on clinical characteristics and the novel discovery of related genes, treatment, and epigenetic modifications in atypical lipomatous tumors.

A Retrospective Study of Superficial Type Atypical Lipomatous Tumor.

Atypical lipomatous tumor (ALT) has been defined as a well-differentiated liposarcoma exhibiting a higher frequency of a local recurrence after surgical resection. ALT is mainly classified into deep type and superficial type. Compared with deep type ALT, superficial type ALT is rarely observed. One of the most important issues is that little has been known about superficial type ALT and it is not easy to predict the presence of superficial type ALT before surgical resection. To clarify the clinical manifestations of superficial type ALT, we examined 15 cases with superficial type ALT and 118 cases with benign lipoma, and analyzed their differences in clinical characteristics and the findings of MRI test. In clinical characteristics, the tumor size of superficial type ALT was significantly greater than that of benign lipoma, and superficial type ALT showed a significantly higher frequency of the tumor size of more than 4 cm. Superficial type ALT exhibited poor tumor mobility and hardness with elastic soft. In addition, a significantly higher frequency of tumor location of superficial type ALT was observed in extremities. Among tumor sites at the trunk, buttocks, and shoulder were high frequent location in superficial type ALT. In an MRI examination, superficial type ALT exhibited a significantly higher frequency of the septal structures compared with benign lipoma. The combinations of clinical characteristics, including physical examinations, MRI, and histological examinations, are helpful for the diagnosis of superficial type ALT.