[Lipoblastoma-like tumor of the vulva: A case report and review of the literature]

Lipoblastoma-like tumor of the vulva (LBLTV) was first described as a benign mesenchymal neoplasia; it was not recognized as a separate diagnosis in the 2013 WHO classification of soft-tissue tumors. To date, only 19 cases have been reported. LBLTV differential diagnosis includes other tumors of the vulvoperineal region and tumors with adipocytic differentiation, most of which are benign and thus a misdiagnosis has few clinical consequences. However, LBLTV may also mimic some aggressive lipomatous neoplasms. We describe a case of LBLTV in a 28 year-old woman and review the literature.

Genome sequencing analysis of a family with a child displaying severe abdominal distention and recurrent hypoglycemia

BACKGROUND

Germline mutations in PTEN are associated with the PTEN hamartoma tumor syndrome (PHTS), an umbrella term used to describe a spectrum of autosomal-dominant disorders characterized by variable phenotypic manifestations associated with cell or tissue overgrowth. We report a boy who developed severe progressive abdominal distention due to a dramatic adipose mass from the age of 7 months and developed recurrent hypoinsulinemic hypoglycemia that led to seizures at the age of 4 years.

METHODS

Trio-based whole-genome sequencing was performed by using blood DNA from the child and his parents. The possible pathogenic variants were verified by Sanger sequencing. Functional characterization of the identified variant was completed by western blot.

RESULTS

The child inherited a single-nucleotide deletion NM_000314.6:c.849delA (p.Glu284Argfs) in the tumor suppressor gene PTEN from his father. The paternal family members have a history of cancer. It is conceivable that PTEN loss-of-function induced the adipose tumor growth and hypoglycemia, although the proband did not meet the usual diagnosis criteria of Cowden syndrome or Bannayan-Riley-Ruvalcaba syndrome that are characterized by germline mutations of PTEN.

CONCLUSION

This case underlines the variability of phenotypes associated with PTEN germline mutations and provides useful information for diagnosis and genetic counseling of PTEN-related diseases for pediatric patients.

Soft Tissue Special Issue: Selected Topics in the Pathology of Adipocytic Tumors

Our understanding of adipocytic tumors classification and diagnosis continues to evolve. We present a brief review and updated summary of selected adipocytic tumors involving the head and neck region. For the practicing pathologist, knowledge of these established and emerging entities is critical for the correct pathologic diagnosis and treatment of the patient.

Compression-induced dedifferentiation of adipocytes promotes tumor progression

Dysregulated physical stresses are generated during tumorigenesis that affect the surrounding compliant tissues including adipocytes. However, the effect of physical stressors on the behavior of adipocytes and their cross-talk with tumor cells remain elusive. Here, we demonstrate that compression of cells, resulting from various types of physical stresses, can induce dedifferentiation of adipocytes via mechanically activating Wnt/β-catenin signaling. The compression-induced dedifferentiated adipocytes (CiDAs) have a distinct transcriptome profile, long-term self-renewal, and serial clonogenicity, but do not form teratomas. We then show that CiDAs notably enhance human mammary adenocarcinoma proliferation both in vitro and in a xenograft model, owing to myofibrogenesis of CiDAs in the tumor-conditioned environment. Collectively, our results highlight unique physical interplay in the tumor ecosystem; tumor-induced physical stresses stimulate de novo generation of CiDAs, which feedback to tumor growth.

Juxtaarticular Myxoma in a Pigtail Macaque (Macaca nemestrina)

A 10-y-old pigtail macaque presented with a subcutaneous, soft-tissue mass overlying the right stifle joint. Here we describe the clinical case and histopathologic and immunohistochemical analysis of this lesion. This case represents the first published report of juxtaarticular myxoma in a pigtail macaque.

[Most musculoskeletal soft tissue tumors are benign]

Most musculoskeletal soft tissue tumors are benign, lipoma being the most common. Malignant soft tissue tumors may be difficult to clinically distinguish from benign. Scandinavian recommendations are that all lesions suspicious for sarcoma be referred to a sarcoma center. This has led to improved tumor control and less post-operative functional deficits. Magnetic resonance imaging (MRI) can reliably diagnose lipomas, and further work-up is not necessary. Lipomas can be treated at the local hospital. All deep seated musculoskeletal tumors (under the muscle fascia) not unequivocally lipomas should be referred to a sarcoma center. All superficial (subcutaneous) musculoskeletal tumors larger than 5 cm and not unequivocally lipomas should be referred to a sarcoma center.

Coexistence of Spindle Cell Lipoma and Ordinary Lipoma

We report a patient with a spindle cell lipoma on the nape and three ordinary lipomas on the abdomen and extremities. The coexistence of spindle cell lipoma and ordinary lipoma in a single patient is rare. Abundant CD34-positive spindle cells and mast cells were found in the spindle cell lipoma, but in the ordinary lipomas, only a small number of CD34-positive spindle cells were found in the interstitial connective tissue and no mast cells were seen. Because mast cells are known to stimulate mesenchymal cell proliferation and collagen production, mast cell infiltration may be a trigger for the proliferation of CD34-positive spindle cells, leading to the conversion of ordinary lipoma into spindle cell lipoma.

[Risk factors for recurrence in pT3aN0M0 renal cell carcinoma according to 2009 TNM classification]

The TNM classification of renal cell carcinoma was updated in 2009. In this new classification system, T3a consists of tumors with renal vein involvement and tumors with fat invasion. To assess risk factors for recurrence, we retrospectively reviewed 89 patients with pT3aN0M0 renal cell carcinoma who underwent radical or partial nephrectomy between 1992 and 2011. Analyzed risk factors for recurrence were age, gender, tumor size, grade, v factor, infiltrative growth (INF), adjuvant interferon, surgical technic (radical or partial), clinical T classification, renal vein thrombus, and pathological fat invasion. The median follow-up was 52.2 months. Five-year recurrence-free survival rate was 69.0%. Within the pT3a subcategory, the five-year recurrence-free survival was 76.7% in patients with fat invasion only, 42.9% in patients with renal vein thrombus only, and 28.6% in patients with the two concomitant features. On univariate analysis, tumor size, grade, INF, clinical T classification, and renal vein thrombus were significantly associated with recurrence. On multivariate analysis, INF (p = 0.023, HR 3.927) was an independent risk factor for recurrence. In pT3aN0M0 renal cell carcinoma, INF significantly affects recurrence, and patients with both fat invasion and renal vein thrombus have worst prognosis.

Cytogenetic analysis in the diagnosis and management of lipoblastomas: results from a single institution

BACKGROUND

Lipoblastomas are rare, benign, soft tissue tumors that occur primarily in young children. Treatment includes complete excision and surveillance for recurrence. Lipoblastomas can be indistinguishable from other benign lipomatous tumors and liposarcomas. Cytogenetic analysis can provide the definitive diagnosis in questionable cases, because benign and malignant lipomatous tumors exhibit specific nonrandom cytogenetic abnormalities. The purpose of the present study was to discuss the disease management and outcomes in a large contemporary group of patients with lipoblastoma.

MATERIALS AND METHODS

A retrospective chart review of patients diagnosed with lipoblastoma presenting from 2000-2011 was conducted. The data from these patients were compared with data from a previously published historical group of patients (1985-1999) from the same children's hospital.

RESULTS

We identified 37 patients in the contemporary cohort group and compared them with 25 patients from the historical group. The tumor involvement sites were similar. The current cohort group had a lower recurrence rate, although this might have been underestimated owing to a shorter follow-up period (median 1.4 y, range 2 wk to 11.0 y). Preoperative imaging findings led to an incorrect diagnosis in 62% of the patients. Cytogenetic analysis was used to help determine the final diagnosis in 50% of the cases. In 39% of cases, translocations involved the long arm of chromosome 8, the most common anomaly in lipoblastoma.

CONCLUSIONS

Lipoblastomas are rare tumors in young children that can be misclassified as other malignant or benign lipomatous tumors with markedly different outcomes and treatments. We recommend that cytogenetic analysis be routinely used for all pediatric lipomatous tumors to provide an accurate diagnosis and guide appropriate therapy and follow-up.

Lipomatous tumors of the oral mucosa: histomorphological, histochemical and immunohistochemical features

We conducted a comprehensive study of all lipomatous tumors of the oral mucosa (1996-2008) accessioned at the Department of Oral Pathology, Tel Aviv University, collected demographic data and analyzed multiple histomorphological features. Furthermore, we examined the immunostaining of aP2 (adipocyte lipid binding protein) and the polarization colors of picrosirius red (PSR)-stained collagen fibers in order to test their potential in differentiating between benign and malignant tumors. All cases were immunohistochemically stained with aP2 antibody; only tumors with considerable collagenous stroma were selected for the PSR staining. A total of 77 tumors were included in the study, 91% benign and 9% malignant. Fibrolipoma (37.7%) and lipoma (36.4%) were the most frequent tumors. Atypical lipomatous tumor (ALT) was the only type of malignancy. The most common location for the benign tumors was the buccal mucosa and for ALT, the tongue. Histomorphological features characteristic of malignant tumors were occasionally present also in the benign entities. Expression of aP2 was similar in all tumors, while the polarization colors of the PSR-stained collagen fibers differed significantly between ALT and benign tumors (p<0.05). Benign and malignant tumors occasionally show overlapping histomorphological features that require a meticulous examination. PSR staining with polarization microscopy could aid in differentiating malignant from benign tumors in equivocal cases.

Giant lipomatous tumors of the upper extremities--a series of 8 consecutive cases

We present a series of eight consecutive patients evaluated in our department from 2002 to 2007 with giant lipomatous tumors (as defined in medical studies as greater than 5 cm) of upper extremities. There were three male and five female, ranged in age from 17 to 77 years (mean age of 55). The tumor's size ranged from 5 to 34 cm. All patients underwent total excision of the tumors with free margins. All specimens were sent to pathology: seven patients had benign tumors and one patient had liposarcoma. There were no recurrences of the tumors. Appropriate preoperative evaluation and complete surgical excision are mandatory for successful treatment of these tumors.

Lipoblastoma--an unfamiliar but important diagnosis. A case series and literature review

Lipoblastoma and its infiltrative variant lipoblastomatosis are rare adipose tissue tumours seen in infants and children. Many surgeons are unfamiliar with these uncommon lesions and hence they are suboptimally treated. We report a case series of six patients in our tertiary paediatric hospital. Cases were reviewed retrospectively with reference to demographics, investigations, diagnosis and their management. Lipoblastomas are easily misdiagnosed and excision before proper investigations may result in incomplete resection, recurrence and further potentially mutilating surgery.

Cutaneous metastatic adenocarcinoma arising from a malignant sacrococcygeal teratoma in an adult

We present a patient with cutaneous metastasis caused by an adenocarcinoma arising from a malignant teratoma. A 37-year-old woman seen for the complaint of swelling in the genital region also complained of a draining mass in her gluteal region present since birth. Physical examination showed marked edema in the labia majora, multiple hyperkeratotic papules in the left labium majus, and erythema, induration, and swelling in the left femoral and inguinal regions. A soft tumor that exhibited sinus tracts was palpated in the left gluteus. Excision of the gluteal tumor revealed a teratoma. Vulvar skin biopsy confirmed a mucinous adenocarcinoma which had derived from this teratoma. A tumor that arises from pluripotent germ cells, teratoma rarely shows malignant transformation. The patient presented is a rare example of a cutaneous metastasis originating from a congenital sacrococcygeal teratoma in an adult.

Tumeurs fibrolipomateuses hémosidérotiques: une nouvelle entité à ne pas méconnaître

Fatty tissues lesions are the most frequent of both benign (lipoma) and malignant tumor (liposarcoma) of soft tissues in the adult. We here describe the case of female patient having a fatty tissue mass of the ankle corresponding to an hemosiderotic fibrohistiocytic lipomatous lesion (HFHLL). This very rare tumour of recent description is specific of the ankle/foot area of the middle age women. These lesions are always benign and frequently recur following incomplete resection. This tumor may have invasive local growth and metastases have not been described so far. We describe the anatomopathologist's key points of their diagnostic. We discuss the main differentials diagnosis and treatment.

Intrapelvic lipoblastoma with massive spinal canal invasion

OBJECTS

The lipoblastoma is a rare benign pediatric neoplasm that derives from embryonic white fat cells. However, this tumor with spinal invasion in children is extremely rare. We report a case of a 3-year-old boy who had lipoblastoma with massive invasion into the lower lumbosacral spinal canal.

CASE REPORT

A 3-year-old boy had suffered from progressive urinary incontinence and uncontrolled defecation during past 3 months. Computed tomography and magnetic resonance imaging scans showed that a large lobulated pelvic cavity mass had invaded the lumbosacral spinal canal. The mass was located over the epidural space from L4 to the lower sacral spinal canal, resulting in the compression of the thecal sac. After total laminectomy from L4 to S3 with flavectomy, a subtotal mass removal for the intraspinal canal mass was done. Histopathologic diagnosis confirmed the lipoblastoma.

CONCLUSION

Lipoblastoma is a rare benign neoplasm and lumbosacral invasion is unique. Complete surgical excision is the treatment of choice. If an incomplete surgical excision is performed, close observation and clinical follow-up must be done because a recurrence is possible.

Island of salivary gland in adipose tissue: a report of three cases

Although uncommon, many variants of lipomatous lesions in or around salivary glands have been reported in the literature. We report a series of three such cases in the minor salivary gland region. The first case (oral floor) is a well-circumscribed lipocytic lesion admixed with glandular components (mucous acini, serous demilunes and ducts). The second case (alveolar mucosa) is a diffuse lipomatous proliferation with entrapped salivary glandular elements, muscles and blood vessels. The third case (palate) is similar to the first case but the gland is located at the periphery of the lesion. The purpose of the article was to report these three lesions and discuss in relation to other pertaining lipomatous lesions (sialolipoma, lipoadenoma, lipomatosis, lipometaplasia in pleomorphic adenoma and infiltrating lipoma).

Intrascrotal lipoblastoma: a case report and review of the literature

Lipoblastomas are rare benign soft tissue tumors that occur primarily in young children. Most lipoblastomas occur in the extremities, trunk, head, and neck. An intrascrotal location is unusual. We describe the case of a 4-year-old boy with an intrascrotal lipoblastoma and discuss the differential diagnosis in reviewing the literature.

Fibrous lipoblastoma with 8q11.2 abnormality

A 3-month-old African American female infant had a rapidly growing lipoblastoma with a prominent fibrous component in the soft tissue of the left lateral knee, which recurred at 10 months. Cytogenetic analysis revealed deletion of 8(q11.2q13) with a 19(q12q13.3) insertion at that site, confirming that this is closely related to the conventional lipoblastoma. The presence of multivacuolated lipoblasts and the staining characteristics (no staining for CD99, CD34, or smooth muscle actin) distinguish this from the recently described lipofibromatosis.

Lipomatous tumors-how we have reached our present views, what controversies remain and why we still face diagnostic problems: a tribute to Dr Franz Enzinger

The group of soft tissue lipomatous tumors constitutes an unusually complex clinical and morphologic mosaic. Over the last 4 decades, there has been great progress in identifying recognizable and reproducible patterns that are of great clinical significance. Through his sharp eyes, analytical and scientific mind, and didactic skills, Dr Franz Enzinger has played a key role in this development. Recent genetic discoveries in the field of lipomatous tumors have confirmed morphologically based theories and provided new insight into pathogenetic mechanisms.

Hibernoma--correlation of histopathology and magnetic-resonance-imaging features in 10 cases

OBJECTIVE, DESIGN AND PATIENTS: Hibernoma is an uncommon, slow-growing, benign soft-tissue tumour resembling brown adipose tissue. The histological appearances are well-documented, but there are relatively few descriptions of the magnetic resonance (MR) imaging features. We report a retrospective comparison of the histological and MR appearances of ten hibernomas of the extremities, classified histologically into lipoma-like [<70% multivacuolated adipocytes (MVAs)] and non-lipoma-like hibernomas (>70% MVAs).

RESULTS

The lipoma-like hibernomas measured 4-27 cm in maximum size. All were well-defined on MR imaging and histology except for one subcutaneous lesion that blended in with surrounding fat histologically. All lesions were isointense with subcutaneous fat on T1- and T2-weighting apart from one lesion that was predominantly slightly hypointense on T1-weighting and predominantly slightly hyperintense on T2-weighting and STIR. Two slightly inhomogeneous lesions contained thin (<5 mm thickness) tortuous vessels. One patient received intravenous contrast, but the lesion did not enhance. The six non-lipoma-like hibernomas measured 2.5-15.5 cm in maximum size and all were unencapsulated. Three were well-defined and three partly ill-defined on MR imaging. There were no significant differences in the MR characteristics of the non-lipoma-like variants. On T1-weighting, the non-lipoma-like hibernomas that contained >90% MVAs were predominantly slightly hypointense to subcutaneous fat. One lesion was isointense with subcutaneous fat, but this lesion only contained from 80-90% MVAs. All non-lipoma-like lesions were slightly hyperintense on STIR but so too were two of the four lipoma-like lesions. Four of the six non-lipoma-like lesions showed marked or moderate inhomogeneity due to thick septa and prominent vessels. Of the two cases that received intravenous contrast, both showed enhancement corresponding to regions of >90% MVAs or prominent vessels within fibrous septa.

CONCLUSIONS

MR imaging has shown some distinguishing features between lipoma-like and non-lipoma-like hibernomas. Lipoma-like hibernomas are usually isointense with subcutaneous fat on T1-weighting, are either homogeneous or slightly inhomogeneous and may contain thin tortuous vascular structures. Non-lipoma-like hibernomas are pre-dominantly slightly hypointense to subcutaneous fat on T1-weighting, often display marked or moderate inhomogeneity with prominent septa and vessels and enhancement is typical. The appearances of non-lipoma-like hibernomas are not diagnostic and may be mimicked by lipoma variants and by well-differentiated liposarcoma or atypical lipoma.

Oncogenic osteomalacia: localization of underlying peripheral mesenchymal tumors with use of Tc 99m sestamibi scintigraphy

OBJECTIVE

To highlight a strategy for potential detection of mesenchymal tumors in oncogenic malacia, as illustrated by 3 cases.

METHODS

Three case reports are presented in which successful localization of the offending neoplasm was accomplished by using whole-body Tc 99m sestamibi scanning. Alternative localization techniques are also reviewed.

RESULTS

Oncogenic osteomalacia occurs infrequently and is caused by neoplasms that secrete phosphatonins, substances that interfere with proximal tubular resorption of phosphorus and can result in phosphaturia, hypophosphatemia, reduced 1,25-dihydroxyvitamin D concentration, and osteomalacia. Removal of the underlying neoplasm results in complete resolution of all biochemical, pathologic, and physical manifestations of this disorder, as shown in our 3 patients. Because the neoplasms are small and can occur in any tissue compartment, they are difficult to localize, a feature that often results in therapeutic failure.

CONCLUSION

We conclude that use of whole-body Tc 99m sestamibi scanning may be an appropriate and cost-effective initial strategy for the localization of peripheral phosphatonin-secreting tumors.

Fat in the liver: diagnosis and characterization

The purpose of this article is to provide an update on imaging techniques useful for detection and characterization of fat in the liver. Imaging findings of liver steatosis, both diffuse steatosis and focal fatty change, as well as focal fatty sparing, are presented. In addition, we will review computed tomography (CT) and magnetic resonance (MR) findings of focal liver lesions with fatty metamorphosis, including hepatocellular carcinoma, hepatocellular adenoma, focal nodular hyperplasia, angiomyolipoma, lipoma, and metastases.

Rearrangement of chromosomal region 8q11-13 in lipomatous tumours: correlation with lipoblastoma morphology

Cytogenetics is of considerable value when diagnosing lipomatous tumours, as different tumour types have different more or less specific chromosomal abnormalities. One such entity is lipoblastoma, which is a benign lipomatous tumour that often exhibits rearrangements of chromosome bands 8q11-13, and the gene PLAG1 has been implicated as the target of these chromosomal changes. All lipomatous tumours karyotyped at the Norwegian Radium Hospital were reviewed, looking for rearrangements of 8q11-13. Five tumours exhibiting chromosomal abnormalities affecting this region were found. Only one of them was morphologically diagnosed as a lipoblastoma, two being classified as lipomas, one as a hibernoma, and one as a well-differentiated liposarcoma. The two tumours successfully analysed with bacterial artificial chromosomes (BACs) covering the gene PLAG1 showed involvement of this gene in the rearrangement. The findings raise the question as to what extent the diagnosis lipoblastoma should be based on histopathological or cytogenetic/molecular data or a combination thereof. When karyotypic information from this series was combined with available literature data, it was found that the sensitivity of 8q11-13 rearrangements for diagnosing lipoblastomas when found in a lipomatous tumour was 77% and that the corresponding specificity was 98%. The validity of these calculations of the diagnostic information provided by the cytogenetic findings is, of course, totally dependent on the morphological diagnosis made in each case. Regardless of what the precise phenotypic diagnosis was, it is suggested that lipomatous tumours with 8q11-13 rearrangement constitute a distinct pathogenetic entity. When selective therapies tailor-made against the specific pathogenetic rearrangement become available, it will become mandatory to pay more attention to the genetic constitution of the tumour cells than to their phenotypic appearance.

Recurrent maturing perineal lipoblastoma

Lipoblastoma is a rare benign neoplasm of fetal adipose tissue that we see mostly in infants and young children less than 3 years of age. Most lipoblastomas occur on the extremities, trunk, head and neck, and various other organs have been described. We report a case of a recurrent perineal lipoblastoma in a 2.5-year-old boy, which showed maturation of the lipoblasts as compared to the primary tumor.

Lipoblastoma of Infancy Mimicking Hemangioma of Infancy

Lipoblastomas are rare benign tumors of infancy that usually affect children younger than 3 years. Most lipoblastomas (70%) occur on the extremities. Lipoblastomas may mimic other infantile tumors, including hemangiomas, hibernomas, lipomas, and liposarcomas, and correct diagnosis is necessary to ensure appropriate treatment. Lipoblastomas fall under 2 discrete subtypes: well-circumscribed lipoblastomas and diffuse lipoblastomatosis. Both types present with firm, nontender masses of lobulated, well-circumscribed soft tissue. Histologically they can be highly vascularized with plexiform capillaries, often with an individual feeder artery to each lobule. Complete surgical removal is the recommended treatment. Only 2 cases of lipoblastomas of the cheek have been reported in the English-language literature. We present the case of a young child with a cheek lipoblastoma, emphasizing the importance of correct diagnosis and highlighting techniques used to provide suitable treatment.

From the archives of the AFIP: benign musculoskeletal lipomatous lesions

Benign lipomatous lesions involving soft tissue are common musculoskeletal masses that are classified into nine distinct diagnoses: lipoma, lipomatosis, lipomatosis of nerve, lipoblastoma or lipoblastomatosis, angiolipoma, myolipoma of soft tissue, chondroid lipoma, spindle cell lipoma and pleomorphic lipoma, and hibernoma. Soft-tissue lipoma accounts for almost 50% of all soft-tissue tumors. Radiologic evaluation is diagnostic in up to 71% of cases. These lesions are identical to subcutaneous fat on computed tomographic (CT) and magnetic resonance (MR) images and may contain thin septa. Lipomatosis represents a diffuse overgrowth of mature fat affecting either subcutaneous tissue, muscle or nerve, and imaging is needed to evaluate lesion extent. Lipoblastoma is a tumor of immature fat occurring in young children, and imaging features may reveal a mixture of fat and nonadipose tissue. Angiolipoma, myolipoma, and chondroid lipoma are rare lipomatous lesions that are infrequently imaged. Spindle cell and pleomorphic lipoma appear as a subcutaneous lipomatous mass in the posterior neck or shoulder, with frequent nonadipose components. Hibernoma appears as a lipomatous mass with serpentine vascular elements. Benign lipomatous lesions affecting bone, joint, or tendon sheath include intraosseous lipoma, parosteal lipoma, liposclerosing myxofibrous tumor, discrete lipoma of joint or tendon sheath, and lipoma arborescens. Intraosseous and parosteal lipoma have a pathognomonic CT or MR appearance, with fat in the marrow space or on the bone surface, respectively. Liposclerosing myxofibrous tumor is a rare intermixed histologic lesion commonly located in the medullary canal of the intertrochanteric femur. Benign lipomatous lesions may occur focally in a joint or tendon sheath or with diffuse villonodular proliferation in the synovium (lipoma arborescens) and are diagnosed based on location and identification of fat. Understanding the spectrum of appearances of the various benign musculoskeletal lipomatous lesions improves radiologic assessment and is vital for optimal patient management.

2-Deoxy-2-[F-18]fluoro-d-glucose—Positron Emission Tomography of the Head and Neck: An Atlas of Normal Uptake and Variants

In the evaluation of tumors of the head and neck region, positron emission tomography (PET) using 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) is increasingly playing a valuable clinical role. However, assessment of this region can be challenging because of the large number of structures in this area which may demonstrate physiologically increased uptake of FDG. Furthermore, these structures are generally small, and uptake patterns can be quite variable, rendering the head and neck region one of the most difficult areas of the body to assess with FDG-PET. To assist in this endeavor, a pictorial of normal FDG uptake, including commonly encountered variants, is presented.

Atypical lipomatous tumor with rare structural rearrangements involving chromosomes 8 and 12

Atypical lipomatous tumor (ALT), an intermediate malignant neoplasm of soft tissues, is characterized by the presence of supernumerary ring and giant marker chromosomes. These supernumerary chromosomes consistently contain amplified 12q-material in association with amplified segments from a variety of other chromosomes. However, a few cases of ALT with other types of chromosomal rearrangements have been reported earlier. We report on new types of structural aberrations in a case of ALT. In a pseudodiploid karyotype, there were two aberrant chromosomes, both consisting of alternating chromosome 8 and 12 sequences as shown by multicolor fluorescence in situ hybridization (FISH). The complex rearrangement was not only the result of multiple breaks and reunions of these chromosomes, but was also associated with a gain of chromosome 12 sequences. FISH analyses revealed that the number of MDM2 signals was slightly elevated (median, 5). There were three intact copies of HMGA2 and one additional copy of the 5' part of the gene. These findings are consistent with previous reports that the ALT phenotype may be associated with a low or moderate level of gene amplification, whereas truncation of HMGA2 has been observed in both ALTs and benign lipomas. The aberrations in the present case were stable, although rare cells with higher MDM2 copy numbers were detected. Whether ALTs with these types of aberrations have a lower risk of tumor progression than ALTs with the notoriously mitotically unstable ring and giant marker chromosomes remains to be investigated.

Tenascin C and cathepsin d expression in adipocytic tumors: an immunohistochemical investigation of 43 cases

Cathepsin D (CatD) and tenascin C (Tn-C) have been implicated in invasion and metastasis of carcinomas. However, little is known about CatD and Tn-C distribution in mesenchymal tumors. Therefore, we aimed to investigate the expression of Tn-C and CatD in adipocytic tumors. Tn-C and CatD expressions in 27 lipomas, 5 atypical lipomatous tumor/well-differentiated liposarcomas (ALT/WDLS) and 11 liposarcomas (LS) were evaluated by immunohistochemistry and scored semiquantitatively. CatD expression was higher in ALT/WDLS than in lipomas (p<0.001), and higher in LS than in ALT/WDLS (p=0.009). Stromal Tn-C expression was higher in ALT/WDLS than in lipomas (p=0.02), but no difference was observed between ALT/WDLS and LS (p>0.05). These results indicate that Tn-C and CatD may be markers of locally aggressive or malignant behavior in adipocytic tumors.

Lipoblastoma in an 11-month-old infant

Lipoblastoma and lipoblastomatosis are rare benign mesenchymal tumors of embryonal white fat, which normally affect children under 3 years. We report an 11-month-old boy who was presented with a painless lump in the suprapubic region, which was diagnosed on ultrasound as herniated omental fat or lipoma.

[Cytomorphological features of the fatty tissue tumors of the liver]

The necrotizing soft tissue infection caused by anaerobic microorganisms or by mixed aerobic-anaerobic flora is one of the most severe infections in surgical practice with a mortality rate up to 75%. Of great importance for successful treatment are the early diagnosis followed by aggressive debridement and adequate antibacterial therapy. Depending on the studies of 358 isolates made in the Clinic of Septic Surgery, we specify the most often used antibiotics in cases of severe anaerobic surgical infection. It is established that the incidence of this severe infection is unpredictable and its spreading depends on the immune answer the concomitant illnesses and the previous undertaken surgeries of the patient.

Mesenchymal Tumours of the Thorax:CT Findings and Pathological Features

Mesenchymal tumours of the thorax are uncommon and may originate from the muscle, bone, cartilage, vessel, nerves, fat and fibrous tissue. These tumours occur at different sites including the lung, pleura, mediastinum or chest wall. Mesenchymal tumours tend to show protean and non-specific imaging characteristics. However, in some instances, the imaging characteristics of the tumour may allow a specific diagnosis to be made, such as with lipoid or vascular tumours.

Chiari I malformation associated with thoracic epidural cord lesion: case report

Many spinal cord lesions have been described previously, in association with Chiari I lesions. The authors report a unique case of a 29-year-old patient with a Chiari I malformation and an upper thoracic epidural lesion causing headaches, dysphagia and Brown-Sequard syndrome. The patient underwent a suboccipital decompression as well as a thoracic laminectomy and resection of the epidural lesion. Pathologic analysis revealed that the thoracic lesion was fibro-adipose tissue. A review of the literature failed to show any other similar cases. We discuss the possible etiologies of this case.

Lipoblastoma in a 23-year-old male: distinction from atypical lipomatous tumor using cytogenetic and fluorescence in-situ hybridization analysis

Lipoblastoma is a rare benign tumor that occurs primarily in infancy and early childhood. We present the rare presentation of a 12 cm sized intramuscular lipoblastoma of the thigh in a 23-year-old patient. On histology, the tumor strongly resembled an atypical lipomatous tumor due to the presence of lipoblasts and atypical stromal nuclei. The very focal lobulation and myxoid change presented the only histological hint towards a lipoblastoma. Cytogenetic and subsequent FISH evaluation of the tumor cells showed a 46,XY, t(8;15) (q12;q25) as chromosomal change with rearrangement of the PLAG1 gene. The present case indicates that lipoblastoma should enter the differential diagnosis of an 'atypical' deep seated fatty tumor in adults. The diagnostic value of cytogenetic/molecular analysis in the differential diagnosis of lipomatous tumors is underscored as well.

Fatty tissue breast lesions

Hamartoma, lipoma and fat necrosis are benign fatty tissue lesions that may present as breast lumps. The mammographic appearance may be distinctive allowing imaging diagnosis without biopsy. The characteristic feature of hamartoma is that of a compressible mass containing radiolucent fat interchanged with dense fibrous connective tissue surrounded by a thin radioopaque pseudocapsule. Lipomas are radiolucent with well-defined thin smooth capsule. Twenty-seven percent of fat necrosis appears as discrete round or oval radiolucent oil cyst with thin capsule and egg-shell calcification.

Lipomatous variant of nasopharyngeal angiofibroma: a case report

Nasopharyngeal angiofibroma is an uncommon benign vascular tumor that occurs in adolescent boys and young men. We describe an unusual histological variant of this entity characterized by a prominent adipose tissue component. The patient was a 35-year-old man with a 20-year history of nasal obstruction. Results of physical examination and angiography demonstrated a nasal mass consistent with a nasopharyngeal angiofibroma. We discuss the differential diagnoses pathologically for this lesion.

Caveolin expression is common among benign and malignant smooth muscle and adipocyte neoplasms

The caveolins belong to a newly described group of membrane-scaffolding proteins. Their presence in benign endothelial cells has been used to discriminate benign from malignant vascular neoplasms. The extent of caveolin expression in cutaneous mesenchymal neoplasms has not yet been evaluated, and thus the diagnostic utility of these antibodies is not yet known. In our study, we immunohistochemically examined a spectrum of tumors derived from smooth muscle and adipocytes for caveolin expression. We found that both benign and malignant smooth muscle tumors and tumors comprised of adipocytes expressed caveolins. The presence of this protein in a range of mesenchymal neoplasms is important to know about as this decreases the reported specificity of a positive finding. It is doubtful that caveolin down-regulation contributes to the pathogenesis of liposarcomas and leiomyosarcomas. This finding also may suggest a common origin between endothelial cells and other mesenchymal cells.

Fat attenuation lesions of the mediastinum

The identification of fat within a focal or diffuse mediastinal lesion significantly narrows the differential diagnosis. In many cases, a specific diagnosis can be suggested on the basis of CT findings. In this article, we illustrate and review the characteristic CT features of common and uncommon fat attenuation lesions of the mediastinum, including focal masses and diffuse abnormalities.

Adrenal lipomatous tumours: a 30 year clinicopathological experience at a single institution

AIMS

Fatty tumours of the adrenal gland are uncommon and their features have received little attention in the literature. The aim of this study is to analyse the features of adrenal lipomatous tumours.

METHODS

The histological features of primary adrenal tumours reported over a 30 year period (1970 to 1999) in Queen Mary Hospital, Hong Kong were reviewed and the clinicopathological features of adrenal lipomatous tumours were analysed.

RESULTS

Adrenal lipomatous tumours were noted in 20 patients (12 men, eight women), and they accounted for 4.8% of the primary adrenal tumours reported. The adrenal fatty tumours comprised 11 myelolipomas, three lipomas, three teratomas, two angiomyolipomas, and one liposarcoma. Calcification or bone was noted in one third (seven of 20) of the adrenal tumours. In some fatty tumours (myelolipoma and angiomyolipoma), the fatty component may be inconspicuous. This is the first report in the English literature of angiomyolipoma and liposarcoma of the adrenal gland.

CONCLUSIONS

Different types of fatty tumours were noted in the adrenal gland. A high index of suspicion should be maintained with an aim of surgical treatment for selected patients with large and symptomatic adrenal lipomatous lesions. Histological confirmation is needed for diagnosis.

[Spindle cell lipoma and 13q deletion: diagnostic utility of cytogenetic analysis]

AIM

Spindle cell lipomas are rare adipose tissues tumors. Histologically, these lesions are composed of mature adipocytes and spindle cells associated with collagen bundles. Spindle cell lipomas are benign tumors that can be difficult to distinguish from malignant tumors such as spindle cell liposarcomas, myxoid liposarcomas or well-differentiated liposarcomas.

RESULTS

We report herein the description of two new cases. The first case was a deeply situated and infiltrating tumor located in the retromastoidian area. The karyotype showed the presence of two chromosomal abnormalities, a partial deletion of the long arm of chromosome 13, del(13)(q12) and a balanced reciprocal translocation t(2;6)(p16~21;p21). The second case was a subcutaneous tumor of posterior cervical localization. The karyotype showed a 13q deletion associated with a complex rearrangement of chromosomes 5, 6 and 10. The presence of the 13q deletion allowed us to confirm the diagnosis of spindle cell lipoma in both cases. This deletion has been previously described in six out the eleven published karyotype reports. The 13q deletion is usually associated with partial monosomy 16. The present case confirms that it can occur independently. The 6p21 rearrangement may also play a role in the pathobiology of this tumor, as suggested by the positive HMGIY expression detected by immunohistochemistry.

CONCLUSION

Our study further illustrates that spindle cell lipomas can infiltrate the surrounding muscle and emphasizes the usefulness of cytogenetic analysis in the differential diagnosis of soft tissue tumors.

Lipoblastoma and lipoblastomatosis in infancy and childhood: histopathologic, ultrastructural, and cytogenetic features

Lipoblastoma is a relatively rare tumor that occurs in infancy and early childhood and arises from embryonic white fat. Although a benign tumor, lipoblastomas tend to recur and may resemble myxoid liposarcoma. The authors report 26 cases over a 15-year period at Texas Children's Hospital. There was a slight female predilection (14F:12M). The most common symptom was a painless mass with or without increasing size. The trunk, extremities, head and neck, retroperitoneum, inguinal canal, peritoneal cavity, and lung were the tumor sites. Most tumors were circumscribed lipoblastomas and the minority were diffuse infiltrative lipoblastomatosis. Reexcision for residual or recurrent tumor was necessary more frequently in patients with lipoblastomatosis. Histopathologic examination and ultrastructural examination revealed cellular neoplasms composed of immature adipocytes with relatively well-defined septa, frequent lipoblasts, a fine vascular network, and often a myxoid appearance resembling myxoid liposarcoma. Cytogenetics was performed in 4 cases with chromosome 8q abnormality being most common. The major concern with lipoblastoma in children is to completely excise the tumor to avoid leaving residual tumor and to prevent recurrences. Confusion with myxoid liposarcoma, well-differentiated liposarcoma, and typical lipomas may occur. Although asymptomatic, lipoblastomas may cause dysfunction of other organ systems due to mass effect. Complete surgical excision with at least 2 years of follow-up is the preferred therapy.

Immunohistochemical profile of galectin-8 expression in benign and malignant tumors of epithelial, mesenchymatous and adipous origins, and of the nervous system

This study aims to investigate whether the immunohistochemical expression of galectin-8 could be used as a diagnostic marker in tumor tissues of various histogenetic origins including specimens from epithelial (n=145), mesenchymatous (n=16), adipous (n=10) and central and peripheral nervous system (n=25) tissue, and 4 mesotheliomas. Immunohistochemical reactions were carried out with a polyclonal anti-galectin-8 antibody and histological slides from tissues derived from the files of the Laboratory of Anatomopathology of University Erasmus Hospital, Brussels. Formalin-fixed paraffin-embedded tissues of 45 normal cases as well as 41 benign and 114 malignant tumors were studied. Marked decreases in immunohistochemical galectin-8 expression were observed in colon (p=0.001), pancreas (p=0.007), liver (p=0.0008), skin (p=0.002) and larynx (p=0.02) tissue when comparing malignant tissue to normal tissue and/or benign tumors. The reverse relationship was observed for breast tissue (p=0.007). No statistically significant differences (p>0.05) were detected when comparing normal tissue and/or benign to malignant tumors in lung, bladder, kidney, prostate and stomach tissue. Significant galectin-8 expression was also measured in non-epithelial tissue including tumors of the central and peripheral nervous system as well as in skeletal muscle and mesotheliomas. Immunohistochemical monitoring of galectin-8 thus reveals an organ-type-dependent regulation of expression upon malignant transformation of various tissue types of epithelial origin. This observation will prompt further studies to delineate any relationship with prognosis.