Lipomatous Component Research Articles

Bridging the spinal dysraphism spectrum between terminal myelocystocele and spinal cord lipoma: a report of two cases of true terminal lipomyelocystocele with holo-cord syrinx.

Terminal myelocystocele (TMC) is a rare form of spinal dysraphism which arises due to aberration in the secondary neurulation process involving the caudal cell mass. Terminal myelocystocele has been defined by Pang et al. based on essential and non-essential features. One of the non-essential features includes non dysraphic lipomas which do not tether to the neural placode. We are presenting two cases which meets all the essential criteria outlined by Pang et al. for TMC but also show the presence of a lipomatous component tethering to the neural placode, similar to a dysraphic lipoma. Through this article, we want to showcase a subset which represents "true" terminal lipomyelocystocele (TLMC), bridging the spectrum of spinal dysraphism between TMC and lipomyelomeningocele (LMM).

Solitary fibrous tumor occurring at unusual sites: A clinico-pathological series of 31 cases with emphasis on its wide morphological spectrum

Solitary fibrous tumor (SFT) is a relatively rare mesenchymal fibroblastic tumor occurring most commonly in adults with no gender predilection. Although the pathological diagnosis of SFT is usually straightforward, some difficulties may occasionally arise mainly due to the wide morphological spectrum exhibited by this tumor. In the present paper we aimed to evaluate the unusual clinicopathological features in a series of 31 SFTs arising from parenchymal organs, superficial soft tissues and deep soft tissues. Our results emphasize that SFTs may occur anywhere, including unusual sites such as periosteum of the thoracic spine, mesorectal tissue, hepatic hilum, paravescial space, kidney and breast. Moreover, a wide morphological spectrum was observed in tumors included in our series. The most striking morphological features observed included: extensive lipomatous component, myxoid stromal changes, epithelioid cell component, metaplastic mature bone, neurofibroma-like, myxofibrosarcoma-like and pseudoalveolar-like areas. Additionally, multinucleated giant cells and sarcomatous dedifferentiation were also identified.Our paper emphasizes that SFT may occur in unusual anatomical locations and exhibits a wide morphological spectrum. Pathologists must be aware of these features to avoid confusion with other benign and malignant neoplasms that may show overlapping morphological features.

Liposarcoma Involving Serous Fluid Cavities-A Case Series Illustrating Clinical Implications and the Diagnostic Role of Exfoliative Cytology.

Introduction: Cytological diagnosis of sarcomas requires detailed cytomorphological assessment and integration of immunocytochemistry and/or molecular testing. The role of exfoliative cytology, as compared to aspiration cytology, is less understood. This case series describes well-differentiated/dedifferentiated liposarcomas in effusions, with cytomorphological features, ancillary test results and clinical outcomes detailed. Methods: A computerized search of the department pathology archives was performed for sarcomatous effusions with histological diagnosis or clinical history of well-differentiated/dedifferentiated liposarcoma. Clinical progress, cytology slides, immunocytochemistry and molecular test results were reviewed. Results: Six patients were identified. In 5 patients with clinical follow up, 4 (80%) were deceased within 5 months of malignant effusion. One patient was alive with 12 years disease-free survival after radical resection with adjuvant radiotherapy. Three patients showed dedifferentiation on histology, and high-grade (dedifferentiated) tumor cells were present in effusion cytology of 2 patients. Two showed well-differentiated components only on biopsy, but high-grade (dedifferentiated) tumor cells were identified in cytology. The high-grade tumor cells displayed marked nuclear irregularity, enlargement, size variation, with macronucleoli and multinucleation. Well-differentiated lipomatous components were demonstrated in 4 patients (66.7%), comprising of multivacuolated lipoblasts and atypical lipocytes. CDK4 and MDM2 immunoreactivity in all 3 cases with cell blocks, and CDK4 and MDM2 amplification in one were successfully demonstrated. Conclusion: Lipomatous and dedifferentiated components can be sampled and cytomorphologically identified on effusion fluids of liposarcomas, with sufficient cellularity for immunocytochemistry and molecular testing. Although generally associated with poor prognosis, long disease-free survival with sarcomatous effusion is possible with radical surgery and adjuvant treatment.

Thymofibrolipoma: a case report and review of the literature

BackgroundThymofibrolipoma has been described as a variant of thymolipoma. To date, 3 cases have been reported, and the lesion have been described to consist of extensive areas of collagenous tissue interspersed with islands of mature adipose tissue and strands of thymic tissue.Case presentationA 43-year-old woman had an anterior mediastinal tumor. Macroscopically, the cut surface of the tumor was composed of a yellowish lipomatous component and a uniform whitish fibrous component with elastic stiffness. Microscopically, the tumor was composed of collagenous fibrous tissue with sparse spindle cells, mature adipocytes and strands or islands of thymic tissue. The spindle cells in the fibrous tissue had monoallelic deletion of the 13q14 region and corresponding loss of RB1 and FOXO1A protein expression.ConclusionsThis case report may strengthen the hypothesis that thymofibrolipoma is a neoplastic lesion and a variant of thymolipoma and that thymofibrolipoma and lipofibroadenoma are different names for the same lesion. The name “lipofibroadenoma” was given to the lesion because of its histological resemblance to fibroadenoma of the mammary gland. However, this name does not reflect the pathogenesis of this lesion, and the name “thymofibrolipoma” would be preferable. It will be necessary to discuss whether lipofibroadenoma should be listed as an independent entity in the WHO classification.

A success of lipomyelomeningocele resection with intraoperative neurophysiological monitoring (IONM) guidance in a 10-year-old child: A case report

Introduction: Lipomyelomeningocele is one of closed spinal dysraphism, inherently associated with tethered cord. Its prevalence ranges between 0.3 and 0.6 per 10.000 live births. Deterioration of bladder and bowel function often manifests before the motor and sensory function. Intraoperative neurophysiological monitoring (IONM) is often used in lipomyelomeningocele surgery to facilitate safe resection of lipomatous components and detethering of the spinal cord due to the absence of a clear boundary between the lipoma and neural placode.This case highlights the critical role of adequate IONM to reduce the complications of lipomyelomeningocele resection surgery. Case Presentation: Here we present a 10-year-old boy with a lump over the back since birth, progressively increased in size, and with a history of urinary and faecal incontinence since one year before admission. There was also hypoesthesia on lumbar 2 spinal cord level. Physical examination of the lumbosacral region revealed a single lump measured about 4.5 x 1.9 x 3.2 cm in size, soft consistency, and immobile. Magnetic resonance imaging of the lumbosacral region revealed a lipomyelomeningocele with tethered cord protruded into the anatomical defect from sacral vertebrae S1-S4. Surgery was indicated because of the neurological symptoms and it was safely performed with the assistance of IONM. There were no postoperative complications after surgery and there was an improvement in the patients' neurological symptoms. Conclusion: IONM in spinal surgery has been proven useful to reduce the postoperative neurological complication by providing identification of neural structures topographically and functionally, therefore, giving a warning alarm during surgery, which can be immediately responded by the surgeons.

Establishment and characterization of NCC-DDLPS5-C1: a novel patient-derived cell line of dedifferentiated liposarcoma.

Dedifferentiated liposarcoma (DDLPS) is a highly aggressive subtype of liposarcoma that is morphologically defined as a transition from a well-differentiated lipomatous component to a non-lipogenic one. Curative therapy for DDLPS is complete resection, and the benefits of current systemic chemotherapy remain marginal. Although DDLPS is molecularly characterized by co-amplification of MDM2 and CDK4 (12q14-15) and detailed genomic analyses have been conducted by multiple research groups, the effects of molecular targeted drugs are marginal, and novel therapeutic modalities are required. Although patient-derived cell lines are pivotal for cancer research, no DDLPS cell lines are currently available from public cell repositories. Accordingly, in this study, we established a novel DDLPS cell line, NCC-DDLPS5-C1, using surgically resected tumor tissues from a patient with DDLPS. NCC-DDLPS5-C1 cells exhibited typical gene amplification, overexpression of MDM2 and CDK4, and other DNA copy number alterations. The NCC-DDLPS5-C1 cells were capable of rapid cell proliferation, aggressive invasion, and spheroid formation, but not tumor formation in mice. We reported the utility of NCC-DDLPS5-C1 cells for a drug-response assay to detect anticancer drugs that significantly attenuated cell proliferation. Thus, we concluded that the NCC-DDLPS5-C1 cell line could be a useful resource for the study of DDLPS. Considering the diversity of disease in terms of clinical outcomes, continuous efforts are required to develop more patient-derived cancer models with different clinical and pathological backgrounds.

Cerebellar liponeurocytoma: clinical, histopathological and molecular features of a series of three cases, including one recurrent tumor

Cerebellar liponeurocytoma (CL) is an unusual tumor, histologically composed of a mixture of small to medium-sized, rounded neurocytic cells and a variable lipomatous component. Although CL was originally considered as a subtype of medulloblastoma, subsequent molecular studies demonstrated that this tumor was a distinct entity, exhibiting the tumor protein p53 gene (TP53) missense mutations in 20% of cases, chromosome 17 deletion, and the absence of mutations in the adenomatous polyposis coli gene (APC), the protein patched homolog gene (PTCH), the kinase insert domain receptor gene (KDR), and the β-catenin gene (CTNNB). Apart from these molecular features, little is known about the pathogenesis and the genetic landscape of CL to date. In order to characterize the mutational landscape of CL and identify alterations that are driving tumorigenesis, we report a series of three cases, including one recurrent tumor, analysed by next-generation sequencing (NGS), which identified a total of 22 variants, of which four were missense mutations, nine were synonymous variants, and nine were located on intronic regions. In particular, DNA sequencing identified missense mutations in APC, KDR, and TP53 that could be implicated in promoting tumor progression and angiogenesis of CL. Furthermore, the NGS analysis revealed that recurrent CL did not have additional genetic changes compared with the primary tumor. Moreover, the high frequencies of detected mutations suggested that the identified alterations are germline variants. Indeed, an additional NGS on the genomic DNA obtained from one of the three patients confirmed the presence of the variants in the germline DNA. In conclusion, the obtained data support the hypothesis that CL is a distinct pathological entity that does not show specific somatic alterations driving tumorigenesis.

Long-standing Renal Hydatid Cyst Mimicking an Angiomyolipoma: A Rare Case Report

Primary hydatid cyst of the kidney is very rare and accounts for 1-4% of all hydatid disease. Authors hereby reports an unusual case of an isolated, long-standing renal hydatid cyst, mimicking an angiomyolipoma on imaging. A 72-year-old female, from a rural area, presented with pain in the right flank since two years. She also complained of mild fever off and on, since one year. A 10×10 cm, non tender lump was palpated in the right flank. Ultrasonography and computerised tomography showed a large rightsided renal mass measuring 10 cms and a diagnosis of angiomyolipoma was rendered. A right sided open/simple nephrectomy was done. The kidney was large, cystic, firm and was sent for histopathological examination. On gross examination, a large, unilocular, thick- walled, cystic lesion was seen. Cut-surface showed heterogeneous, creamy coloured necrotic contents, with few nodular gelatinous masses. On microscopy, characteristic acellular, laminated structure of the ectocyst of Echinococcus granulosus was seen. Extensive calcification and ossification of the cyst wall with bone marrow production was also seen. Contents of the cyst were necrotic and no daughter cysts were seen. Adipose tissue of the bone marrow was mistaken on imaging for the lipomatous component of an angiomyolipoma. Isolated renal hydatid cyst is very uncommon and though active hydatid cysts do have characteristic radiological findings, they can be misdiagnosed as a benign renal tumours. Renal cysts or abscesses. Old cases show degenerative changes as well as calcification and are difficult to diagnose preoperatively. Surgical treatment of renal hydatid cyst depends on the size, number of cysts, exact intrarenal location and residual renal function.

Lipomatous hemangiopericytoma of the larynx: An extremely rare tumor at an unusual location

Hemangiopericytoma (HPC) arising from the contractile pericyte of Zimmerman comprises less than 1% of the vascular tumors with approximately 200 cases documented in the literature, out of which only 11 cases are reported in the larynx. Lipomatous hemangiopericytoma (LHPC) is an uncommon histological variant composed of a mixture of HPC and mature lipomatous component with around 50 cases reported so far, and majority have been found in the deep soft tissue of the lower extremities and retroperitoneum. HPCs are closely related to solitary fibrous tumors, and the LHPC was designated as a separate entity according to recent the World Health Organization classification of soft tissue tumors in 2002. To the best of our knowledge, even on extensive search of literature, LHPC of the larynx has not been reported till date. We report an extremely rare case of LHPC in a middle-aged female presented with a mass in the arytenoid cartilage of the larynx.

Synchronous Renal Dedifferentiated Liposarcoma and Retroperitoneal Well-Differentiated Liposarcoma: A Case Report With Literature Review.

Liposarcoma is the most common soft tissue malignancy and usually occurs in the retroperitoneum or the extremities but rarely in the kidney. In this article, we report a case of a 71-year-old female patient who presented with abdominal lump and left flank pain for 1 month. An abdominal contrast-enhanced computed tomography scan demonstrated a 12 cm × 7 cm solid mass arising from the upper pole of left kidney and another 8 cm × 6 cm low-density retroperitoneal mass with fat density. Radical nephrectomy of the left kidney and resection of the retroperitoneal mass were performed. Surprisingly, pathological examination revealed a high-grade sarcoma (with minor lipomatous component) in the left kidney and a retroperitoneal well-differentiated liposarcoma. MDM2 gene amplification was identified by fluorescence in situ hybridization in both tumors, supporting final diagnosis of dedifferentiated liposarcoma of the kidney and well-differentiated liposarcoma of the retroperitoneum.

Cutaneous Eccrine Adenolipoma with a Spindle Cell Component

Abstract Introduction/Objective Cutaneous adenolipoma is a rare, benign variant of solitary lipoma characterized by a mature adipocytic proliferation with entrapped eccrine or apocrine sweat glands. It is found predominately in middle-aged females, with a predilection for lower extremities including the thigh and gluteal regions. Cutaneous adenolipoma is presumed to be a hamartomatous process. Herein, we report a unique case of a cutaneous eccrine adenolipoma with a spindle cell component, namely, an early evolving spindle cell adenolipoma. Methods A 43-year-old female with a recurrent history of hidradenitis presented with a 2.7 cm x 1.5 cm x 0.7 cm soft, mobile nodule on the right posterior thigh. It had been present for at least four months and clinically resembled a lipoma. An excisional punch biopsy was performed for pathological evaluation. A concurrent nevus lipomatosus superficialis was diagnosed from the right perineum. Results Gross examination of the thigh nodule revealed fragments of a tan-yellow, lobulated, fatty lesion. Microscopic examination demonstrated a benign lipomatous proliferation with entrapped eccrine glands associated with a surrounding spindle cell stroma. Initial differential diagnosis included a cutaneous eccrine adenolipoma variant and a cutaneous mixed solitary hamartoma composed of admixed neural, eccrine and lipomatous components. Immunohistochemical staining showed uptake for CD34 and CD10 in the spindle cell stromal component, but negative for desmin and S100. Based on our histopathological findings, our diagnosis of an eccrine cutaneous adenolipoma with a spindle cell component was rendered. This unique lesion displayed features of an evolving spindle cell lipoma with entrapped sweat glands, which may be viewed as an early stage of a dermal spindle cell adenolipoma. Conclusion Cutaneous eccrine adenolipoma is a rare, benign lipomatous neoplasm with entrapped sweat glands that can also show a spindle cell component. We share this rare lesion exemplifying the histomorphological spectrum of a lipomatous hamartoma and to highlight the recognition of a cutaneous adenolipoma.

Malignant Phyllodes Tumor with Lipomatous Differentiation: A Unique Presentation

Abstract Casestudy Phyllodes tumors (PT) are uncommon biphasic fibroepithelial neoplasms that account for <1% of all breast tumors. The distinction between benign and malignant PTs is made based on a number of histologic characteristics, including an infiltrative margin, stromal overgrowth, mitotic count, hypercellularity and atypia. 30% of cases show heterologous differentiation, which mostly occurs in stromal elements. This can result in a wide range of tumor histopathology including lipomatous areas. Results We present the case of a 46-year-old female with a 3.1 cm left breast palpated mass and no significant past medical history. Ultrasound guided needle biopsy revealed multiple foci of hypercellular spindle cells with marked atypia and mitoses (ki-67: 40–60%) surrounded by focal fat necrosis. Immunohistochemical staining was negative for CK 5/6, p63, CAM 5.2, SMA, desmin, AE1/3, CD163, nuclear beta-catenin and CD34. The patient subsequently underwent a wire localization excisional biopsy. Microscopic examination revealed a biphasic hypercellular lesion with both stromal and distorted glandular elements and extensive lipomatous differentiation. Although mostly well- circumscribed, some infiltration into the surrounding tissue was identified as well as nuclear atypia and an increased mitotic rate (10 mitoses/HPF). The diagnosis of malignant phyllodes tumor with lipomatous differentiation was made based on these findings. FISH was performed and was negative for MDM2, suggesting that the lipomatous component itself was not malignant (i.e. liposarcoma) Conclusion Malignant phyllodes tumors rarely show heterologous differentiation. A literature review revealed that most lipomatous differentiation was liposarcomatous with rare cases of pure lipomatous metaplasia. Although malignant phyllodes tumor have the highest rate of metastasis relative to their benign counterparts, complete excision has resulted in a mortality rate of approximately 12%. The clinical implications of lipomatous differentiation are currently unknown. However, in these cases ensuring the lack of malignant liposarcomatous tumor growth is imperative.

What Are the Results of Resection of Localized Dedifferentiated Liposarcomas in the Extremities?

Dedifferentiated liposarcoma (DDLPS) is a rare malignancy that transitions from an atypical lipomatous tumor to a sarcoma with a variable morphologic appearance. The behavior of this tumor in the retroperitoneum is aggressive, but the behavior of DDLPS in the extremities is less well-defined because it is rare. Few reports have assessed the imaging features and clinical outcomes of primary DDLPS in the extremities. In patients with primary DDLPS of the extremity, we asked the following questions: (1) How frequently do additional primary malignancies occur in patients with DDLPS? (2) What is the rate of overall survival, metastases, and local recurrence in DDLPS? (3) What factors are associated with metastasis-free survival and local recurrence in DDLPS? We defined DDLPS as a biphasic neoplasm that transitions from an atypical lipomatous tumor (ALT) to a sarcoma of variable morphologic appearance and histologic grades. We retrospectively evaluated the medical records of patients with DDLPS of the extremities who underwent surgery in our institution between 2003 and 2017. During that time, 16 patients were treated for this diagnosis; one was excluded from this study because the patient did not have an MRI, leaving 15 patients (nine men, six women; their median [range] age was 67 years [42 to 87]) for evaluation. All had a minimum of 2 years follow-up (median [range] 54 months [25 to 136]); 14 of 15 have been seen in the last 5 years (one patient, who was doing well at the time, was lost after 9 years of follow-up). In 11 patients, MRI demonstrated two components: an ALT component with high intensity on both T1-weighed and T2-weighted sequences and a dedifferentiated component low-to-intermediate intensity on T1-weighed and heterogeneous hyperintensity on T2-weighted sequence. Nine patients were evaluated using 2-deoxy-2-18F-fluoro-D-glucose positron emission tomography (FDG-PET) combined with CT (PET/CT). PET/CT showed a biphasic pattern with a close relationship to MRI findings. The dedifferentiated component presented with high FDG uptake (median [range] maximum standardized uptake value 5.1 [1.9 to 22.6]), while the atypical lipomatous tumor component showed almost no FDG uptake. In all patients, immunohistochemical studies of p16 and cyclin-dependent kinase-4 (CDK4) were investigated. Positive staining for both p16 and CDK4 were seen in 13 of 15 patients.We retrospectively evaluated the electronic medical records of all patients in our institution for the presence of additional primary malignancies, local recurrence-free survival, metastasis-free survival, and overall survival. The survival rate was estimated using the Kaplan-Meier method. The Wilcoxon exact test was used to determine the prognostic importance of the following survival variables: age, sex, maximum tumor size, radiotherapy, and surgical margin. Seven additional primary malignancies developed in five of 15 patients (two lung cancers, two sarcomas, one renal cell cancer, one uterine cancer, and one non-Hodgkin lymphoma). The 3- and 5-year metastasis-free survival rates were 86% (95% CI 0.67 to 1.00) and 75% (95% CI 0.49 to 1.00), respectively. With the numbers available, we found no factors associated with metastasis-free survival. The 3- and 5-year overall survival rates were 100% (95% CI 1.00 to 1.00) and 88% (95% CI 0.65 to 1.00), respectively. Three of 15 patients had local recurrence. The 3- and 5-year local recurrence-free survival rates were 86% (95% CI 0.67 to 1.00) and 75% (95% CI 0.49 to 1.00), respectively. Large (> 15 cm) tumors were more likely to have a local recurrence (p = 0.04). In this small series, we found that the extremities are a favorable site for DDLPS compared with the retroperitoneum, although we did not directly compare the two sites. This rare tumor has a relatively high likelihood of being associated with other malignancies. We believe patients should be assessed and monitored carefully for this possibility. In the future, larger studies are needed to better define predictors of local recurrence, although the tumor's size may be associated with a greater propensity for local recurrence. Level II, prognostic study.

A Cheek Mass in a 5-Year-Old Child

To describe the management of a 5-year old female with a painless, mobile cheek mass. A retrospective chart review of presentation, imaging, pathology and management. Magnetic resonance imaging showed a heterogenous mass with solid and lipomatous components. The mass was a lipoblastoma on histopathology and was excised completely with no evidence of recurrence. The diagnosis and management of a cheek mass in a child is challenging. Imaging is important but not diagnostic. Surgical excision is the primary management of a lipoblastoma.

Spectrum of gastrointestinal tract pathology in a multicenter cohort of 43 Cowden syndrome patients

Most patients with Cowden syndrome have lesions in the gastrointestinal tract, characterized by multiple polyps of various histologic types in the large bowel, polyps in the upper gastrointestinal tract, and esophageal glycogenic acanthosis. However, pathologists are often unaware of the distinctive polyposis phenotype of Cowden syndrome. In this multicenter study, we report the spectrum of gastrointestinal manifestations in a series of 43 Cowden syndrome patients who had at least one endoscopy. The median age at the first endoscopy was 46 years and 58% were women. In 24 of 29 (83%) tested patients, a pathogenic germline mutation in PTEN was identified. The histology from 199 endoscopy procedures (67 upper gastrointestinal endoscopy and 132 colonoscopies) was reviewed. Hamartomatous polyps of the large bowel were the most common lesions, present in 85% of patients. Hamartomatous polyps showed varied histology, including lymphoid aggregates in 55% of patients, a lipomatous component in 52%, a ganglioneuromatous component in 52%, and a fibrous-rich component in 14%. Polyps with at least two different stromal components were found in 55% of patients. Inflammatory polyps were present in 21% of patients. Conventional adenomas and serrated polyps were identified in 48% and 62% of patients, respectively. In the upper gastrointestinal tract, the most common lesions were esophageal glycogenic acanthosis (37%), gastric hamartomatous polyps (47%), and duodenal hamartomatous polyps (20%). All patients with glycogenic acanthosis who had a colonoscopy had hamartomatous polyps of the large bowel. In five patients, the diagnosis of Cowden syndrome was established after the pathology report raised suspicion for the diagnosis. Pathologists who are aware of the characteristic admixture of lesions in Cowden syndrome can play an essential role in recommending referral to genetic counseling and gene testing. Early diagnosis of Cowden syndrome is important, as these patients and their relatives are at increased risk for developing multiple cancers.

Diagnostic Utility and Limitations of Immunohistochemistry of p16, CDK4, and MDM2 and Automated Dual-color In Situ Hybridization of MDM2 for the Diagnosis of Challenging Cases of Dedifferentiated Liposarcoma.

The diagnosis of dedifferentiated liposarcoma (DDLPS) is challenging when an atypical lipomatous tumor component is absent or obscure. To analyze the utility and limitations of ancillary techniques, we studied 11 cases of DDLPS in challenging conditions and 17 cases of nonlipogenic high-grade sarcomas with immunohistochemistry (IHC) for p16, CDK4, and MDM2 and automated dual-color in situ hybridization (DISH) for MDM2 amplification. All DDLPS specimens lacked clear lipogenic components and were immunoreactive for p16, CDK4, and MDM2. DISH analyses also revealed high-level amplification of MDM2 in all DDLPS. In contrast, among nonlipogenic sarcomas, p16, CDK4, and MDM2 were expressed in 8, 9, and 3 cases, respectively. MDM2 amplification was detected in 3 of 8 studied. The MDM2-amplified tumors were the same as the MDM2-immunoreactive tumors. After careful reevaluation of these 3 sarcomas, 2 were reclassified as DDLPS because small areas of lipogenic components were detected in the original specimens. The respective sensitivities and specificities of these markers were as follows: p16 IHC (100% and 60%), CDK4 IHC (100% and 53.3%), MDM2 IHC (100% and 93.3%), and MDM2 DISH (100% and 83.3%). The results of MDM2 IHC completely coincided with those of MDM2 DISH. The present study confirmed the substantial utility of MDM2 IHC and MDM2 DISH in the diagnosis of DDLPS, especially when lipogenic components were indistinct compared with IHC for p16 and CDK4. Furthermore, automated DISH was more practical than fluorescent in situ hybridization.

Angioleiomioma renal con patrón inmunohistoquímico miogénico y melanocítico como variante del angiomiolipoma

We present a case of a 67 year old male with a cortical nodular tumour of the left kidney. During a year's follow-up with ultrasound and MRI, the tumour was seen to increase in size by 16-20 mm. The nodule was surgically removed. Microscopically it was well defined and unencapsulated, with a proliferation of typical fusiform cells of smooth muscle cell appearance, clumped around well vascularized areas.Immunohistochemically, the neoplasm was positive for muscle markers (smooth muscle actin, desmin and caldesmon) and melanocyte markers (HMB-45 and Melan A). Our case would appear to be a renal neoplasm with an angioleiomyomatous pattern, but with immunohistochemical characteristics of angiomyolipoma (PEComa), however, without either a lipomatous or lipid cell component. We found no previous reports of this type of tumour in the literature.

Dedifferentiated liposarcoma composed predominantly of rhabdoid/epithelioid cells: a frequently misdiagnosed highly aggressive variant

Dedifferentiated liposarcoma is one of the most common sarcoma types in adults with a predilection for the retroperitoneum. We have recently encountered 6 cases of DDL composed predominantly of rounded, rhabdoid or epithelioid cells mimicking rhabdoid melanoma, epithelioid rhabdomyosarcoma or undifferentiated carcinoma. Patients were 5 males and one female aged 64 to 81 years (median, 68). Tumors originated in the retroperitoneum (n=5; 3 in the psoas muscle) and deep soft tissue of the thigh (n=1). All 3 patients with follow-up died of metastatic disease within 4 to 8 months. Preoperative biopsy diagnoses never suggested dedifferentiated liposarcoma as a possibility; instead carcinoma, rhabdomyosarcoma and lymphoma were on top of suggestions. Five resected tumors were composed predominantly (70%-100%) of anaplastic rounded to oval rhabdoid cells with prominent central nucleoli and paranuclear rhabdoid inclusions. Bi- and multinucleation was a constant feature. The background stroma showed variable myxoid changes and minor mixed inflammatory cells. Two cases showed homologous dedifferentiation and another had sclerosing spindle cell nodule but a well-differentiated lipomatous component was not seen in any. One biopsied case showed solely monotonous small round blue cells with scattered rhabdoid cells. Immunohistochemistry showed expression of MDM2 (6/6), CDK4 (5/6), pancytokeratin AE/1AE3 (4/6) and diffusely desmin and myogenin (2/6). All cases showed high-level co-amplification of MDM2/CDK4 by in situ hybridization. The SWI/SNF complex components (SMARCB1, SMARCA2, SMARCA4, ARID1A and PBRM1) were intact in all cases. This highly aggressive liposarcoma variant needs to be distinguished from a variety of neoplasms including undifferentiated carcinoma, melanoma, lymphoma, rhabdomyosarcoma and others.

Lipomatous tumors of the breast: A contemporary review.

Breast tumors with lipomatous or liposarcomatous components are infrequently encountered, but can be a source of diagnostic difficulty if the context of the fatty differentiation is not recognized. Among the true adipocytic tumors, lipoma is the most common lipomatous tumor arising in the breast. Several mammary spindle cell tumors may show adipocytic differentiation, including fibroepithelial tumors and myofibroblastoma. Liposarcomatous components most often arise in malignant phyllodes tumors, as opposed to primary liposarcomas of the breast which are believed to be uncommon. This article will review the spectrum fat-containing tumors of the breast with an emphasis on differential diagnosis and insights from recent molecular studies.

Tumeurs adipeuses

Adipocytic tumors are the most common mesenchymal neoplasms, liposarcoma accounting for approximately 20% of soft tissue sarcomas. The differential diagnosis between benign and malignant tumors is often problematic and represents a significant proportion of consultation cases. The goal of this article is to review liposarcoma subtypes, the main benign adipocytic neoplasms: lipoblastoma, hibernoma, spindle/pleomorphic cell lipoma, chondroid lipoma, as well as non adipocytic neoplasms with a lipomatous component such as lipomatous solitary fibrous tumor, emphasizing on practical differential diagnosis issues, and immunohistochemical and molecular tools allowing their resolution.