Clinical, Diagnostic, and Treatment Characteristics of Orbital Liposarcoma

PURPOSE

To clarify the clinical, diagnostic, and treatment characteristics of orbital liposarcoma.

DESIGN

Retrospective observational case series.

METHODS

A review was performed of electronic medical records, histopathology, radiological images, and follow-up information for 21 patients with orbital liposarcoma.

RESULTS

The predominant clinical manifestation of this disease was painless exophthalmos. The most frequently encountered pathological types were well-differentiated and myxoid liposarcoma. Preoperative radiological images from 15 patients showed that orbital liposarcoma initially developed in extraocular muscle in 9 patients. Furthermore, all well-differentiated liposarcomas exhibited the radiographic characteristics of irregular and ill-defined adipose tissue, whereas only 12.5% of myxoid liposarcomas had the imaging characteristics. For the patients who exclusively underwent surgery, all of those with subtotal excisions experienced recurrence, 63.6% of marginal excisions recurred, and 50% of wide excisions resulted in recurrence. However, none of the patients who underwent marginal excisions or wide excisions combined with adjuvant radiotherapy exhibited recurrence. The analysis of magnetic resonance imaging findings in 3 patients who underwent neoadjuvant radiotherapy revealed that the tumor size remained stable in a patient with well-differentiated liposarcoma, whereas another patient with the same type of tumor exhibited a gradual increase in size. Conversely, a patient with myxoid liposarcoma experienced a significant reduction in tumor size following neoadjuvant radiotherapy.

CONCLUSION

Orbital liposarcoma demonstrated a propensity for developing in the extraocular muscle. The radiological images of orbital well-differentiated liposarcomas were characterized by irregular and ill-defined adipose tissue. Surgery combined with radiotherapy demonstrated potential in reducing recurrence rates. Notably, orbital myxoid liposarcoma exhibited greater sensitivity to radiotherapy compared to well-differentiated liposarcoma.

Clinical and surgical effectiveness of the multi-disciplinary standardized management model in the treatment of retroperitoneal liposarcoma: Evidence-based clinical practice experience from Fudan Zhongshan

BACKGROUND

To assess the correlation between clinical outcomes and diagnostic accuracy of evaluations carried out by a preoperative multidisciplinary team versus standard surgical care for patients with retroperitoneal liposarcoma undergoing surgery.

METHODS

This comparative study was conducted retrospectively at a specialist assessment center within Zhongshan Hospital, Fudan University, China, between April 2011 and March 2021. Patients were assigned to a multidisciplinary team or nonmultidisciplinary team cohort based on referral to the multidisciplinary team. The primary outcome measured was long-term clinical prognosis, with other outcomes including diagnostic accuracy, 30-day reoperation, duration of stay, perioperative mortality, and medical complications. To mitigate selection bias, we conducted propensity-score matching. Uni- and multivariable Cox proportional hazard models were then used to evaluate the effect of multidisciplinary teams on postoperative survival. The previously specified questionnaire was used to measure the enhancement of awareness and treatment adherence facilitated by multidisciplinary team management. Data analysis was carried out between January 2023 and August 2023.

RESULTS

Of the 521 records that were screened, 139 patients were deemed eligible for inclusion and defined as the multidisciplinary team cohort. At the same time, 382 patients without multidisciplinary team management were also included during that period and defined as the nonmultidisciplinary team cohort. The multidisciplinary team cohort exhibited lower numbers of primary retroperitoneal liposarcoma but a higher tumor grade and a greater proportion of R2 resection. After propensity-score matching, the 1-, 3-, and 5-year overall survival rates were 89.5%, 70.5%, and 62.9%, respectively, in the multidisciplinary team cohort, and 77.1%, 49.8%, and 45.1% in the nonmultidisciplinary team cohort. The diagnostic consistency of the multidisciplinary team group was significantly superior to that of the nonmultidisciplinary cohort (92.5% vs 83.6%, P = .042). Although no significant links were shown with duration of stay (P = .232) and 30-day reoperation (P = .447), the multidisciplinary team participation was linked to a substantial decrease in perioperative mortality (P = .036) and postoperative complications (P = .002). Additionally, the multidisciplinary team group indicated stronger illness awareness and postoperative adherence among individuals with retroperitoneal liposarcoma.

CONCLUSION

The study's findings indicate that multidisciplinary team management could result in improved clinical outcomes, higher diagnostic accuracy, and reduced duration of postoperative stays, complications, and perioperative mortality. The intervention may also enhance disease awareness and postoperative compliance in retroperitoneal liposarcoma patients who undergo surgery. However, evidence quality was deemed low, and prospective studies with robust designs are required. Nonetheless, these results are worth considering.

Atypical lipomatous tumor/well differentiated liposarcoma and related mimics with updates. When is molecular testing most cost-effective, necessary, and indicated?

The classification and work-up of adipocytic neoplasms remains challenging and sometimes controversial. Since its initial description by Dr. Enterline, the variety of subtypes and morphological appearances considered to represent the spectrum of atypical lipomatous tumor/well differentiated liposarcoma (ALT/WDL) has expanded, resulting in significant morphologic overlap with other entities, including the recently described atypical spindle cell/pleomorphic lipomatous tumor (ASPLT), conventional spindle cell/pleomorphic lipoma (SPL), and so-called "low-grade" forms of dedifferentiated liposarcoma (DL). Nevertheless, the distinction of most examples of ALT/WDL from lipomas/lipoma-like lesions is easily performed on routine histologic examination but can be problematic if the characteristic atypical cells are poorly represented, particularly in small biopsy specimens, obscured by other cellular elements (inflammation), or simply not recognized. The discovery that lipomatous tumors harbor specific and unique karyotypes and molecular events has resulted in ancillary tests that can help provide more accurate diagnoses, especially in less-than-optimal scenarios. Confirmation of MDM2 immunohistochemical over-expression and detection of the MDM2 gene rearrangement via fluorescent in situ hybridization (FISH) have proven particularly reliable and useful. While FISH analysis for MDM2 gene amplification may be helpful for confirming (or excluding) ALT/WDL, it also can lead to overutilization and overdependence. Furthermore, a small subset of otherwise typical ALT/WDL lack MDM2 gene amplification, employing alternative molecular pathways. The recent recognition of ASPLT has introduced a tumor easily mistaken morphologically for ALT/WDL, often exhibiting bizarre and pleomorphic lipoblasts, but lacking the underlying molecular abnormalities and subsequent risk of dedifferentiation. ASPLT also have overlapping features with the better-established SPL but with a greater tendency to locally recur and more frequent involvement of the distal extremities. The precise criteria separating cellular forms of ALT from what some consider "low grade" forms of DL remains controversial and inconsistently applied, even among individual pathologists within institutions. Given their underlying shared cytogenetic abnormality, molecular testing has no utility in this distinction. Herein is a comprehensive historical overview of ALT/WDL, with updates on its distinction from other similar lipomatous tumors and DL, including practical evidence-based criteria for the appropriate cost-effective use of MDM2 testing.

MDM2 Amplification Status in a Cohort of Well-Characterized Myxofibrosarcoma: A Clinicopathologic Analysis of 22 Tumors

Myxofibrosarcomas (MFS) present as slowly enlarging superficial masses in elderly patients. Even though these tumors fail to exhibit a distinct immunophenotype, diagnosis is straightforward when they present in subcutaneous tissue. Intramuscular MFS, however, are more challenging to diagnose as the differential also includes dedifferentiated liposarcoma with myxoid features. The vast majority of dedifferentiated liposarcomas show MDM2 amplification, whereas limited data exists as to the MDM2 status of MFS. We sought to explore the rate of MDM2 amplification in cases of classic MFS. Our archives were searched for MFS; only subcutaneous well-sampled resections were included. FISH for MDM2 amplification was performed on each tumor. A cohort of myxoid dedifferentiated liposarcoma resections was studied for comparison. Twenty-two MFS arose in patients aged 44 to 85 years. All tumors contained an infiltrative population of atypical cells embedded in a myxoid stroma with curvilinear blood vessels. MDM2 amplification by FISH was identified in 3 (of 22; 14%) tumors. Available follow up on 17 patients (range 1-96 months; median 13 months) revealed 6 patients with local recurrence and 1 with distant metastasis. Of 3 patients with MDM2- amplified MFS, 1 experienced recurrence and died of unrelated causes, while the second was alive without disease 12 months after diagnosis. Even though the rate of MDM2 amplification by FISH in MFS appears to be low, a subset of cases may show this genetic alteration, which pathologists should be aware of to avoid misclassification as myxoid dedifferentiated liposarcomas. Further studies are necessary to determine if amplification status adds prognostic value.

Atypical Spindle Cell/Pleomorphic Lipomatous Tumor

Atypical spindle cell/pleomorphic lipomatous tumor (ASCPLT) is a rare soft tissue neoplasm, commonly arising in the subcutis (more common than deep soft tissue) of limbs and limb girdles during mid-adulthood. ASCPLT is histologically a lipogenic neoplasm with ill-defined margins composed of a variable amount of spindle to pleomorphic/multinucleated cells within a fibromyxoid stroma. ASCPLTs lack MDM2 amplification, but a large subset show RB1 deletion and variable expression of CD34. Though initially thought to be the malignant form of spindle cell lipoma, ASCPLTs are benign with local recurrences (∼10-15%) and no well-documented dedifferentiation or metastasis.

Myxoid Pleomorphic Liposarcoma

Myxoid pleomorphic liposarcoma (MPLPS) shows a strong predilection for the mediastinum and can affect a wide age range. Clinically, MPLPS exhibits aggressive behavior and demonstrates a worse overall and progression-free survival than myxoid/round cell liposarcoma (MRLPS) and pleomorphic liposarcoma (PLPS). Histologically, MPLPS is characterized by hybrid morphologic features of MRLPS and PLPS, including myxoid stroma, chicken wire-like vasculature, univacuolated and multivacuolated lipoblasts, and high-grade pleomorphic sarcomatous components. In terms of molecular features, MPLPS is distinct from other lipomatous tumors as it harbors genome-wide loss of heterozygosity.

Nodular cystic fat necrosis: a distinctive rare soft-tissue mass

We report the case of a 34-year-old female who was evaluated for a right lower extremity soft-tissue mass, found to be a large cystic lesion bound by fibrous tissue containing innumerable, freely mobile nodules of fat. Her presentation suggested the diagnosis of nodular cystic fat necrosis (NCFN), a rare entity that likely represents a morphological subset of fat necrosis potentially caused by vascular insufficiency secondary to local trauma. Her lesion was best visualized using MRI, which revealed characteristic imaging features of NCFN including nodular lipid-signal foci that suppress on fat-saturated sequences, intralesional fluid with high signal intensity on T2-weighted imaging, and a contrast-enhancing outer capsule with low signal intensity on T1-weighted imaging. Ultrasound imaging offered the advantage of showing mobile hyperechogenic foci within the anechoic cystic structure, and the lesion was otherwise visualized on radiography as a nonspecific soft-tissue radiopacity. She was managed with complete surgical excision with pathologic evaluation demonstrating, similar to the radiologic features, innumerable free-floating, 1-5 mm, smooth, nearly uniform spherical nodules of mature fat with widespread necrosis contained within a thick fibrous pseudocapsule. Follow-up imaging revealed no evidence of remaining or recurrent disease on postoperative follow-up MRI. The differential diagnosis includes lipoma with fat necrosis, lipoma variant, atypical lipomatous tumor, and a Morel-Lavallée lesion. There is overlap in the imaging features between fat necrosis and both benign and malignant adipocytic tumors, occasionally making this distinction based solely on imaging findings challenging. To our knowledge, this is the largest example of NCFN ever reported.

Intra-Abdominal and Retroperitoneal Benign Lipomatous Tumors-An Extremely Rare Mimic of Liposarcoma and its Diagnostic Challenge

Background. Lipomas are common superficial soft tissue tumors of mature adipocytes. In contrast, well-differentiated/dedifferentiated liposarcoma typically presents in the retroperitoneum as large masses. We provide clinicopathologic and follow-up details of 9 retroperitoneal/intra-abdominal benign lipomatous tumors (BLT) and discuss the utility of ancillary fluorescence in situ hybridization (FISH) in distinguishing from their malignant counterparts. Design. Clinicopathologic details and histology of 9 intra-abdominal and retroperitoneal lipomas were studied along with ancillary CD10 immunohistochemistry (IHC) and FISH for MDM2 and CDK4 amplification. Results. There were 6 females and 3 males. Median age at diagnosis was 52 years (range 36-81 years). Seven were identified incidentally and 2 presented with primary complaints. On imaging, 7 were considered suspicious for liposarcoma. Grossly, the tumors ranged from 3.4 to 41.2 cm (median 16.5 cm). Histologically, all cases showed well-differentiated BLT, further classified as lipoma (n = 7; 1 with metaplastic ossification, 2 with prominent vessels, and 4 ordinary lipomas) and lipoma-like hibernoma (n = 2)-the latter 2 showed intramuscular lesions with interspersed brown fat. CD10 IHC showed strong staining in the 2 hibernomas, whereas the staining was weak in the remaining. MDM2 and CDK4 amplification were negative by FISH in all. Follow-up (median 18 months) did not show recurrence on clinical or imaging evaluation. Conclusion. Retroperitoneal/intra-abdominal BLT are extremely rare and are indistinguishable clinically and radiographically from liposarcoma. This necessitates molecular confirmation even when the histology is convincingly benign, for a confident diagnosis. Our cohort shows that conservative excision without removal of abutted organs is sufficient in most cases.

MDM2 FISH testing criteria in adipose tissue tumors with mature adipocytic morphology - A resection case-based study

The current criteria for utilizing MDM2 Fluorescence In Situ Hybridization (FISH) in adipose-derived tumors were first introduced in 2015 and have been widely adopted. However, these criteria may fail to identify some atypical lipomatous tumors / well-differentiated liposarcoma (ALT/WDL) with mature adipocytic morphology in clinical practice, possibly due to the fact that the existing criteria are primarily based on biopsy cases. Hence, a criterion based on resection cases is needed. In this study, we included 87 adipose tissue tumors with mature adipocytic morphology which were first resected, as well as 9 consultation cases and 25 recurrent resection cases. The final diagnosis was based on MDM2 amplification status. Among the 87 first-time resection cohort, MDM2 FISH amplification was observed in only 2 (5%) of the 39 superficial cases. Marginal infiltration was significantly different in both the MDM2 FISH negative and positive groups (p < 0.05). Of the 37 intramuscular tumors, 17 (46%) showed MDM2 FISH amplification. The MDM2 amplification positive group had a larger tumor size than MDM2 amplification negative group (p = 0.042). Tumors of larger size (≥11 cm) were highly correlated with MDM2 amplification (p = 0.003), but still, 35.3% of the MDM2 amplification-positive cases had tumor sizes less than 11 cm. Eight (66.7%) out of twelve retroperitoneal/ pelvic cases were MDM2 FISH positive. Among the 25 recurrent cases, twenty (80%) of them had MDM2 FISH amplification. In conclusion, we recommend MDM2 FISH for: 1. superficial cases with marginal infiltration based on adequate margin sampling; 2. all intramuscular tumors, retroperitoneal/pelvic tumors and recurrent tumors, both in resection cases and biopsy cases.

Orbital Liposarcoma Progression From a Well-Differentiated to a Dedifferentiated Type in a Young Patient

A young male patient presented with unilateral proptosis of the left eye. Laboratory tests and an initial computed tomography scan of the orbit were compatible with euthyroid orbitopathy. He subsequently underwent decompression surgery for unfavorable cosmesis and corneal exposure symptoms with good results, but returned 1 year later for recurrence of proptosis. There was a superomedial fatty density extraconal mass on computed tomography scan. A biopsy done a year later confirmed the diagnosis of well-differentiated liposarcoma from the previously noted mass and a dedifferentiated component in the newly appeared mass in the intraconal space. Orbital exenteration with radial forearm free flap was performed followed by orbital radiotherapy. No disease recurrence or metastasis was seen on follow-ups for 7 years since undergoing treatment.

Epithelioid dedifferentiated liposarcoma: A clinicopathological and molecular study of 6 cases

In this study, we present six cases of epithelioid dedifferentiated liposarcoma to further characterize its clinical and pathological features. The patients are all adult men with age at presentation ranging from 46 to 64 years (median 58.5 years). The patients presented with nonspecific symptoms of retroperitoneal mass, intermittent dull pain or discomfort. None of the patients had any prior history of a primary tumor. Radiological examinations revealed the presence of ill-demarcated heterogenous mass located in the deep soft tissue, including retroperitoneum (4 cases), pelvis and trunk (1 case each). Grossly, they appeared as solid tumors with focal areas of necrosis being presented in 2 cases. Histologically, all tumors were characterized by sheets of epithelioid cells that displayed marked cellular atypia and brisk mitotic activity. Variable portion of atypical lipomatous tumor/well-differentiated liposarcoma was present in 3 cases. By immunohistochemistry, the high-grade epithelioid component in all 6 cases showed strong and diffuse nuclear staining of MDM2, CDK4 and P16, with partial expression of AE1/AE3 in 3 cases. Fluorescence in situ hybridization analysis revealed high-level amplification of MDM2 in all 6 cases, with co-amplification of CDK4 in 3 cases. Follow up information showed that two patients died of the disease within one year despite multidisciplinary treatment. Due to the striking epithelioid appearance, this rare variant of dedifferentiated liposarcoma may be confused with undifferentiated epithelioid sarcoma, poorly differentiated carcinoma, mesothelioma or other malignancies with epithelioid phenotype. The study presented herein further highlights the aggressive clinical behavior of this unique tumor type. For patients with advanced disease, CDK4 inhibitor may provide an optional targeted treatment.

[Large excoriated pleomorphic liposarcoma]

Pleomorphic liposarcoma is a rare and aggressive tumour developed from mesenchymal tissue. The clinical presentation is most often a subcutaneous mass syndrome. The surgical excision of such lesions has both a therapeutic and diagnostic confirmation value. We here report the case of a 41-year-old woman with a voluminous gluteal lesion that required surgical treatment.

Liposarcoma of spermatic cord mimicking an inguinal hernia A case report and review of the literature

AIM

Liposarcoma of the spermatic cord (LSC) is a tumour often mistaken for common inguinal swelling as hernia and the aim of this work is to present our case with a review of the Literature to define the management of this rare condition.

MATERIAL OF STUDY

A systematic review has been realised, considering English language articles published on Pubmed, between 1956 and 2022, using as key words "Liposarcoma of the spermatic cord".

RESULTS

160 studies described 420 cases of LSC and in 40 cases the patient had undergone surgery with an initial diagnosis of inguinal hernia.

DISCUSSION

LSC is a very rare entity of genitourinary malignancies, occurring more often in the spermatic cord and diagnosis can be difficult. Our case and Literature data confirm the role of imaging in not conventional inguinal swelling, to avoid diagnostic mistakes and to define preoperatively the correct surgical management.

CONCLUSIONS

Imaging is mandatory in case of diagnostic doubt. The recommended treatment is a radical high orchiectomy with clear margins. A long follow-up period is necessary to detect a local recurrence which may occur even several years after the primary therapy.

KEY WORDS

Inguinal swelling, Liposarcoma, Spermatic cord.

A Contemporary Clinicopathologic Analysis of Primary Sarcomas of the Perinephric Soft Tissue and Hilar Vessels Including a Subset Secondarily Involving the Kidney

A variety of primary malignant mesenchymal neoplasms can arise from the perinephric soft tissue and hilar vessels and potentially involve the kidney, mimicking primary renal tumors. A search was made at our institution for patients that underwent radical nephrectomy with associated perinephric or hilar sarcomas from 2010 to 2021. Twenty-six patients were identified. Mean patient age was 60 years (range: 34-83 years), with 16 (62%) females and 10 (38%) males. The mean tumor size was 21.6 cm (range: 8.1-36.5 cm). Among the perinephric/retroperitoneal sarcomas, 14/20 (70%) were dedifferentiated liposarcoma, 4/20 (20%) were well-differentiated liposarcoma, and 2/20 (10%) were leiomyosarcoma. There were 4 grade 1 (20%; all well-differentiated liposarcoma), 9 grade 2 (45%), and 7 grade 3 (35%) tumors. All 6 sarcomas arising from the renal vein/inferior vena cava were leiomyosarcoma: grade 2 in 1 (17%), grade 3 in 4 (67%), and ungraded (due to neoadjuvant therapy effect) in 1 (17%) patient. Four of the 26 (15%) tumors involved the ipsilateral kidney. All 4 tumors were grade 3 sarcomas. On follow-up, 8/26 (31%) patients developed local recurrence and/or metastasis. The mean time for recurrence was 22 months (range: 7-48 months). Two patients progressed with metastasis to the lungs, both of which were grade 3 leiomyosarcoma, and appeared 11 months after the initial diagnosis. Our data suggest that while local recurrence is prevalent with most subtypes of perinephric sarcomas, high-grade leiomyosarcoma has a distinct proclivity for distant metastasis, with the lungs being the most common site.

Biology and Management of Deep-seated Atypical Lipomatous Tumor of the Extremities

Adipocytic neoplasms are frequently encountered in clinical practice. Atypical lipomatous tumor (ALT) is a locally aggressive but non-metastasizing adipocytic neoplasm that primarily occurs in the proximal extremities of middle-aged to older adults. Histologically, ALT is divided into adipocytic (lipoma-like), sclerosing and inflammatory subtypes. The sclerosing subtype is an unfavorable prognostic factor for local recurrence. ALT is characterized by supernumerary ring and/or giant rod chromosomes. These rings and giant markers invariably contain amplified sequences originating from the long arm of chromosome 12, including the MDM2 proto-oncogene (MDM2) and cyclin-dependent kinase 4 (CDK4) gene. MDM2 and/or CDK4 nuclear immunopositivity is present in most cases. Confidently differentiating deep-seated ALT from deep-seated ordinary lipoma is often difficult on imaging. Moreover, the sclerosing subtype may mimic a higher grade liposarcoma. Detection of MDM2 amplification by fluorescence in situ hybridization would be helpful diagnostically for ALT in more difficult cases. The standard treatment for deep-seated ALT is surgery. Although there is no consensus on the best surgical approach for deep-seated ALT of the extremities, the use of marginal resection is acceptable to preserve musculoskeletal function. This review provides an overview of the current knowledge on the clinical and imaging characteristics, pathogenesis, histopathology, and management of deep-seated ALT of the extremities.

Prognostic factors and outcomes of adult spermatic cord sarcoma. A study from the French Sarcoma Group

PURPOSE

To evaluate the outcomes of adult patients with spermatic cord sarcoma (SCS).

METHODS

All consecutive patients with SCS managed by the French Sarcoma Group from 1980 to 2017 were analysed retrospectively. Multivariate analysis (MVA) was used to identify independent correlates of overall survival (OS), metastasis-free survival (MFS), and local relapse-free survival (LRFS).

RESULTS

A total of 224 patients were recorded. The median age was 65.1 years. Forty-one (20.1%) SCSs were discovered unexpectedly during inguinal hernia surgery. The most common subtypes were liposarcoma (LPS) (73%) and leiomyosarcoma (LMS) (12.5%). The initial treatment was surgery for 218 (97.3%) patients. Forty-two patients (18.8%) received radiotherapy, 17 patients (7.6%) received chemotherapy. The median follow-up was 5.1 years. The median OS was 13.9 years. In MVA, OS decreased significantly with histology (HR, well-differentiated LPS versus others = 0.096; p = 0.0224), high grade (HR, 3 versus 1-2 = 2.7; p = 0.0111), previous cancer and metastasis at diagnosis (HR = 6.8; p = 0.0006). The five-year MFS was 85.9% [95% CI: 79.3-90.6]. In MVA, significant factors associated with MFS were LMS subtype (HR = 4.517; p < 10-4) and grade 3 (HR = 3.664; p < 10-3). The five-year LRFS survival rate was 67.9% [95% CI: 59.6-74.9]. In MVA, significant factors associated with local relapse were margins and wide reresection (WRR) after incomplete resection. OS was not significantly different between patients with initial R0/R1 resection and R2 patients who underwent WRR.

CONCLUSIONS

Unplanned surgery affected 20.1% of SCSs. A nonreducible painless inguinal lump should suggest a sarcoma. WRR with R0 resection achieved similar OS to patients with correct surgery upfront.

Rare paratesticular localization of dedifferentiated liposarcoma: Case report and review of the literature

RATIONALE

Dedifferentiated liposarcoma is defined as a malignant tumor that changes its shape from a well-differentiated liposarcoma to a non-liposarcomatous form. Most paratesticular liposarcomas manifest as an inguinal, painless, slow-growing mass. The standard treatment is extensive surgical excision, radiotherapy being proposed for cases with positive margins, those with recurrence, or in cases of the existence of unfavorable prognostic factors.

PATIENT CONCERNS

We present the case of a young patient diagnosed initially with left hydrocele, which after 2 years proved to mask a differentiated liposarcoma of the spermatic cord. The initial clinical manifestations were represented by the increase in volume of the left groin-scrotal region and pain at this level.

DIAGNOSIS

Microscopic examination in hematoxylin-eosin staining highlighted the presence of lipoblasts and fibroblasts in association with areas of hemorrhage and tumor necrosis. The performed immunohistochemical tests confirmed the diagnosis of dedifferentiated liposarcoma. To support and confirm the presence of the mouse double minute 2 homolog gene mutation, chromogenic in situ hybridization analysis was performed.

INTERVENTIONS

The initial treatment was the surgical one. After 2 weeks, the patient received zolendronic acid for hypercalcemia which was caused by the osseous metastasis.

OUTCOMES

The patient died secondary to acute renal failure caused by hypercalcemia despite the treatment received.

LESSONS

This case underlines the importance of both the correct management of oncological patients, as well as immunohistochemical and genetic tests in the identification of prognostic factors, with the ultimate goal of administering an appropriate oncological treatment.

Pleomorphic Liposarcoma Revisited

Pleomorphic liposarcoma (PLPS) is the rarest and more aggressive subtype of liposarcomas, accounting for 10% of all liposarcomas. The diagnosis should be considered after the detection of multivacuolated pleomorphic lipoblasts in biopsy specimens. Wide-margin resection is the treatment of choice. Complementary treatment options, such as radiation therapy and chemotherapy, are debatable in terms of their contribution to curing patients with PLPS. This article reviews the clinical, histopathological, and molecular characteristics of PLPS and discusses the latest trends in the management, therapeutic strategies, and novel investigations of the subject. [Orthopedics. 2023;46(2):e72-e80.].

Atypical Spindle Cell and Pleomorphic Lipomatous Tumor of the Ocular Adnexa: Two Cases of a Rare Entity

Atypical spindle cell and pleomorphic lipomatous tumor (ASCPLT) is a rare lipomatous neoplasm that was recently introduced into the World Health Organization Classification of Soft Tissue and Bone tumors as a distinct entity. ASCPLT has potential for local recurrence but does not metastasize. This biologic behavior separates ASCPLT from its morphologic mimics. Ocular adnexal ASCPLT has not been previously reported. Described herein are two patients with ASCPLT. The subcutaneous orbital rim lesion featured markedly pleomorphic spindle and multinucleated cells. The eyelid lesion was dominated by atypical spindle cells in a background of mature adipocytes. Both neoplasms demonstrated infiltrative margins, rare mitotic figures, immunoreactivity for CD34 and loss of Rb1, and the absence of MDM2 amplification by fluorescence in situ hybridization. Recognition of ASCPLT in the differential of ocular adnexal neoplasms may lead to a re-evaluation of morphologically similar tumors, which may have varied biologic behavior and warrant a different management approach.

Head pleomorphic sarcoma showing murine double minute 2 amplification without a well-differentiated liposarcoma component in a pediatric patient

BACKGROUND

Murine double minute 2 (MDM2) is an oncogene that inhibits p53, leading to decreased apoptosis. Sarcomas showing MDM2 amplification are rare among pediatric patients.

CASE

A 14-year-old boy presented with pleomorphic sarcoma of the head showing MDM2 amplification without a well-differentiated liposarcoma component. Although chemotherapy was initially performed to reduce the tumor size before surgery, the tumor did not shrink. The patient underwent complete surgical resection. Microscopic examination revealed a positive surgical margin; thus, postoperative proton-beam radiotherapy was performed. 3 years after the therapy, no sign of recurrence was observed.

CONCLUSION

Macroscopic surgical resection combined with adjuvant postoperative radiotherapy was effective against MDM2-amplified pleomorphic sarcoma refractory to neoadjuvant chemotherapy in a pediatric patient.

[A case report of adult primary soft tissue sarcoma of the head and neck]

Head and neck primary soft tissue sarcoma is a rare adult connective tissue malignant tumor derived from mesenchymal tissue, which can occur in the paranasal sinuses, throat or neck space.The clinical manifestations are local spread masses in the head and neck or difficulty breathing, swallowing, etc al. MRI and enhanced CT examination are the most commonly used to diagnose such diseases. Pathological diagnosis requires immunohistochemistry combined with FISH to detect MDM2 and CDK4. In this report，two cases of primary soft tissue sarcoma were reported,one is parotid high-differentiated liposarcoma and the other is laryngeal dedifferentiated leiomyosarcoma, introducing the characteristics diagnosis and treatment, and reviewing the relevant literature.

Silver In Situ Hybridization for the Rapid Assessment of MDM2 Amplification in Soft Tissue and Bone Tumors. Validation Based on an Audit of 192 Consecutive Cases Evaluated by Silver In Situ Hybridization and Fluorescence In Situ Hybridization

The discovery of almost invariable mouse double minute 2 (MDM2) amplification among atypical lipomatous tumors (ALT)/well-differentiated liposarcoma and dedifferentiated liposarcoma is incorporated into the contemporary diagnostic workup of fatty lesions. MDM2 amplifications are also found frequently in intimal sarcomas and in low-grade osteogenic sarcoma. At present, fluorescence in situ hybridization (FISH) is the reference test for MDM2 assessment. We are interested in evaluating silver in situ hybridization (SISH) for this purpose. Between October 2016 and May 2020, in 192 consecutive cases requiring MDM2 FISH, SISH was also performed concurrently, including 77 (40.1%) core biopsies and 115 (58.9%) surgical specimens. The mean patient age was 61.0 years. SISH results were available overnight or within 48 hours if repeat testing was required. FISH results were available within 2 to 5 weeks. The cost of SISH was one third of FISH. FISH demonstrated MDM2 amplification in 44 cases (23.6%), was negative in 144 cases (74.4%) and nondiagnostic in 4 decalcified cases (2.0%). SISH showed MDM2 amplification in 33 cases (17.2%), no amplification in 119 cases (62.0%), and indeterminate results because of poor signal in 40 (20.8%) cases. All 33 (100%) SISH-amplified tumors and 113 of 119 (95.0%) nonamplified results were confirmed by FISH. There were no clear differences in the performance of SISH on NCB versus surgical specimens. The overall performance indices of SISH are sensitivity 75%, specificity 78.5%, positive predictive value 100%, and negative predictive value 95.8%. FISH is not required when SISH is clearly amplified. This is clinically useful and improves efficiency. Nonamplified SISH results provide early indications of the likely FISH findings, but there is a 4.2% chance of FISH being positive. At present, the main drawback of SISH is the high rate of nondiagnostic tests. Optimization of SISH signal detection to reduce the proportion of indeterminate results is our current focus.

FISH Diagnostic Assessment of MDM2 Amplification in Liposarcoma: Potential Pitfalls and Troubleshooting Recommendations

MDM2 amplification represents the leading oncogenic pathway and diagnostic hallmark of liposarcoma, whose assessment is based on Fluorescence In Situ Hybridization (FISH) analysis. Despite its diagnostic relevance, no univocal interpretation criteria regarding FISH assessments of MDM2 amplification have been established so far, leading to several different approaches and potential diagnostic misinterpretations. This study aims to address the most common issues and proposes troubleshooting guidelines for MDM2 amplification assessments by FISH. We retrospectively retrieved 51 liposarcomas, 25 Lipomas, 5 Spindle Cell Lipoma/Pleomorphic Lipomas, and 2 Atypical Spindle Cell Lipomatous Tumors and the corresponding MDM2 FISH analysis. We observed MDM2 amplification in liposarcomas cases only (43 out of 51 cases) and identified three MDM2-amplified patterns (scattered (50% of cases), clustered (14% of cases), and mixed (36% of cases)) and two nonamplified patterns (low number of signals (82% of cases) and polysomic (18% of cases)). Based on these data and published evidence in the literature, we propose a set of criteria to guide MDM2 amplification analysis in liposarcoma. Kindled by the compelling importance of MDM2 assessments to improve diagnostic and therapeutic liposarcoma management, these suggestions could represent the first step to develop a univocal interpretation model and consensus guidelines.

Paratesticular Dedifferentiated Liposarcoma with Rhabdomyoblastic Differentiation: A Case Report and Review of the Literature

Liposarcomas of the paratesticular tissue is a rare pathological entity. The symptoms are similar to inguinal hernias or hydroceles. We present the case of an 84-year-old man with a rare paratesticular liposarcoma that manifested as painless right hemiscrotal swelling. Testicular tumour markers were negative. Imaging revealed a heterogeneous mass with a fat component. He underwent a radical orchiectomy on the left side to remove the associated mass. This revealed dedifferentiated liposarcoma (DDLS) with rhabdomyoblastic differentiation and MDM2 amplification. The surgical margins were negative, and the patient had a metastatic workup that included magnetic resonance imaging (MRI) of the abdomen and pelvis. Because of the disease's rarity, there is no clear agreement on radiotherapy and chemotherapy roles.

INSM1 Expression in Mesenchymal Tumors and Its Clinicopathological Significance

BACKGROUND

Insulinoma-associated protein 1 (INSM1) has been identified as a nuclear marker of neuroendocrine tumors. Although INSM1 appears to be a subtle and specific biomarker for neuroendocrine tumor, its expression and clinicopathological significance in mesenchymal tumors remain unclear.

METHODS

We analyzed INSM1 mRNA level in GEO database and conducted immunohistological staining to detect the expression of INSM1 on 576 mesenchymal tumors from pathology department of Tongji Hospital.

RESULTS

At transcription level, INSM1 expression in AITL (angioimmunoblastic T-cell lymphoma) was higher than their adjacent normal tissues as well as Hodgkin's lymphoma. Moreover, INSM1 expression in well-differentiated liposarcoma (WDLPS) was significantly higher than normal fat (P = 0.014) and dedifferentiated liposarcoma (DDLPS) (P = 0.0248). At protein level, the positive rate of INSM1 in AITL was 18/48 (47.4%), while in DDLPS was 9/20 (45%). INSM1 expression in AITL was significantly higher than Hodgkin's lymphoma (P = 0.008). And INSM1 expression in WDLPS was significantly lower than DDLPS (P = 0.015).

CONCLUSION

The combination of GEO data and immunohistochemistry data indicated that the expression level of INSM1 was higher in AITL compared with normal control, suggesting that INSM1 may be involved in pathogenesis of AITL. The abnormal expression of INSM1 was found in WDLPS, and the positive rate of INSM1 was higher in DDLPS than in WDLPS. INSM1 may be involved in the regulation of liposarcoma development. There were significant differences in the expression of INSM1 between AITL and Hodgkin's lymphoma and WDLPS and DDLPS. These findings may assist in the differential diagnosis of these tumors when common markers are difficult to identify, enriching the diagnostic index system of mesenchymal tumors.

[Pleomorphic liposarcoma arising in an unusual site. A case report]

Liposarcomas are the most common group of malignant mesenchymal neoplasms. They usually occur in the extremities and the retroperitoneum and only rarely in the intestine. We report the case of a 75-year-old man presenting with severe anaemia. A CAT scan revealed a 5cm thickening of the jejunal loop, arousing the suspicion of a neoplasm. A partial resection of the small intestine was performed. Macroscopy showed a 12×6cm ulcerated, polypoid mass. Microscopically, a well circumscribed, ulcerated tumour was seen, which had well-defined margins with the surrounding normal mucosa. It consisted of pleomorphic lipoblasts within a sarcomatous background. Very few cases of intestinal liposarcomas have been published and the majority report well-differentiated or undifferentiated liposarcomas. We present a case of a pleomorphic liposarcoma of the small intestine, which is an unusual location and emphases the importance of a comprehensive differential diagnosis.

Dedifferentiated liposarcoma found in ovary: A rare case report

RATIONALE

Dedifferentiated liposarcoma (DL) of the ovary is a rare mesenchymal tumor which is difficult to diagnose before surgery. The diagnose of DL was depended on the morphology, Immunohistochemical stains, and fluorescence in situ hybridization after the complete surgical resection.

PATIENT CONCERNS

We report a case of 63-year-old postmenopausal female who presented with a large pelvic mass and was initially thought to be an original ovarian tumor. However, it was subsequently considered to be a DL arising from the mesentery and developing in ovary.

DIAGNOSIS

Ovarian DL.

INTERVENTIONS

Bilateral salpingo-oophorectomy.

OUTCOMES

Until now, there is no recurrence symptoms represented in the patient after surgery for 12 months.

LESSONS

DL happening in ovary is rare. In this case, the exact origin of the mass still remains ambiguous because of the lack of morphological evidence. Although retroperitoneum is the most common area of DL origin, we for long suspect that the mass was initially derived from mesentery and developed in ovary. A long-term may help confirm the exact origin of the tumor. Complete surgical resection plays an important role in the treatment.

In situ hybridization to detect DNA amplification in extracellular vesicles

EVs have emerged as an important component in tumour initiation, progression and metastasis. Although notable progresses have been made, the detection of EV cargoes remain significantly challenging for researchers to practically use; faster and more convenient methods are required to validate the EV cargoes, especially as biomarkers. Here we show, the possibility of examining embedded EVs as substrates to be used for detecting DNA amplification through ultrasensitive in situ hybridization (ISH). This methodology allows the visualization of DNA targets in a more direct manner, without time consuming optimization steps or particular expertise. Additionally, formalin‐fixed paraffin‐embedded (FFPE) blocks of EVs allows long‐term preservation of samples, permitting future studies. We report here: (i) the successful isolation of EVs from liposarcoma tissues; (ii) the EV embedding in FFPE blocks (iii) the successful selective, specific ultrasensitive ISH examination of EVs derived from tissues, cell line, and sera; (iv) and the detection of MDM2 DNA amplification in EVs from liposarcoma tissues, cell lines and sera. Ultrasensitive ISH on EVs would enable cargo study while the application of ISH to serum EVs, could represent a possible novel methodology for diagnostic confirmation. Modification of probes may enable researchers to detect targets and specific DNA alterations directly in tumour EVs, thereby facilitating detection, diagnosis, and improved understanding of tumour biology relevant to many cancer types.

Thymic Dedifferentiated Liposarcoma Having a Leiomyosarcomatous Dedifferentiated Component

We report an extremely rare case of 42-year-old man, d iagnosed with thymic dedifferentiated liposarcoma (DDL) having a leiomyosarcomatous dedifferentiated component. The tumor was composed of atypical spindle cells. The morphological atypia was also observed around thymic adipose tissue. Immunohistochemically, the spindle cells were positive for desmin, smooth muscle actin, MDM2 and CDK4. MDM2 and CDK4 were also positive for the thymic adipose tissue. MDM2 amplification was confirmed by fluorescence in situ hybridization. Although there are some reports of mediastinal leiomyosarcoma, DDL may be overlooked. For accurate diagnosis of mediastinal mesenchymal tumor, careful observation of thymic adipose tissue is required with immunohistochemical study.

Hydrocele with Paratesticular Liposarcoma

Paratesticular liposarcoma (PLS) is a rare type of genitourinary malignancy in the spermatic cord presenting as scrotal swelling. In this case study, we report an 82-year male who presented with prolonged left scrotal swelling and pain that did not respond to analgesic treatment for one week. His ultrasound confirmed increased fluid content in the left scrotal compartment in the form of septated hydrocele, and hydrocelectomy was planned. During the operation, infected fluid was drained. The testicle and surrounding tissues were infected; hence, left orchiectomy was performed. The pathological examination revealed a dedifferentiated liposarcoma. To our knowledge, this is the first report of liposarcoma of the spermatic cord with hydrocele in the literature. Key Words: Liposarcoma, Spermatic cord, Scrotal swelling, Hydrocele.

Well-differentiated mesenteric liposarcoma: report of two cases

Liposarcoma is a rare tumor that can be treated by surgery in the absence of distant metastases. Management of liposarcoma, including diagnosis and therapy, is challenging because it has no characteristic symptoms and no established effective treatment. Here, we report two rare cases of primary mesenteric liposarcoma. In the first case, the tumor caused small bowel obstruction, and the patient presented with abdominal distention and severe abdominal pain. The second case is an occasional finding that occurred during laparoscopic surgery for incisional hernia. Both patients underwent successful resection of the tumor. Histopathology found a well-differentiated liposarcoma in both cases.

[Diagnostic value of MDM2 RNA in situ hybridization in atypical lipomatous tumor/well-differentiated liposarcoma and dedifferentiated liposarcoma]

Objective: To investigate the value of MDM2 RNA in situ hybridization (RNA-ISH) in diagnosing atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) and dedifferentiated liposarcoma (DDL). Methods: A total of 26 ALT/WDL/DDLs diagnosed from March 2017 to May 2019 in West China Hospital, Sichuan University, Chengdu, China and 18 control cases were included. MDM2 RNA-ISH was performed on all samples and compared with the fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) regarding their performance in detecting MDM2. Results: All samples were detected successfully using the three methods. Among 26 ALT/WDL/DDLs, all cases showed MDM2 amplification and positivity for MDM2 RNA-ISH (26/26, 100%). Twenty-four (24/26, 92.3%) of the 26 tested cases were positive for MDM2 IHC while two of them were negative. Eighteen control cases were all negative for MDM2 FISH and RNA-ISH, and 15 (15/18) cases were negative for MDM2 IHC. The sensitivity and specificity of RNA-ISH were both 100%, and those of MDM2 IHC were 92.3% and 83.3%, respectively. Diffuse staining was identified in all MDM2 RNA-ISH positive ALT/WDL/DDLs, but identified in only 8/24 (33.3%) of the MDM2 IHC positive cases. Among the 11 ALT/WDL/DDL samples evaluated on tissue microarray, the positive rate of MDM2 RNA-ISH was 100% with diffuse staining in all cases. The positive rate of MDM2 IHC was 9/11 while only 1 of the 9 cases showed diffuse staining. The result of MDM2 RNA-ISH was identical to that of MDM2 FISH and was overall consistent with that of MDM2 IHC (Kappa=0.763, P<0.001). Conclusions: In ALT/WDL/DDLs, results of MDM2 RNA-ISH are highly consistent with those of FISH. MDM2 RNA-ISH is more sensitive and more specific and has more diffuse positive signals than the IHC. The findings indicate that MDM2 RNA-ISH is highly valuable for the diagnosis and differential diagnosis of ALT/WDL/DDLs.

Synchronous Occurrence of Advanced Gastric Carcinoma with Retroperitoneal Liposarcoma: A Case Report

BACKGROUND Gastric carcinoma (GC) remains one of the most common and deadly neoplasms in the world. Liposarcoma (LPS) is the most common sarcoma of adults. However, synchronous or metachronous occurrence of GC with LPS seems to be very rare. Tumor staging and differential diagnosis with these cases are extremely difficult. CASE REPORT The patient was a man in his 70s, who reported anorexia and weight loss of 4 kg over 2 months. Gastroscopy demonstrated a large tumor of Borrmann type 3, of which histology was moderately to poorly differentiated adenocarcinoma. The clinical stage was initially defined as IVb due to a 11×6 cm retroperitoneal (RP) tumor. Despite chemotherapy for GC, the RP tumor rapidly enlarged. Endoscopic ultrasound-guided fine-needle aspiration biopsy showed that it was an undifferentiated sarcoma. He died of hepatorenal failure secondary to severe jaundice. The autopsy revealed a synchronous occurrence of GC and RP sarcoma. GC had no areas admixed with sarcoma. Histology of RP sarcoma showed that it mainly consisted of undifferentiated sarcoma and focally of well-differentiated LPS characterized by well-differentiated adipocytes admixed with scattered atypical stromal cells. The tumor cells in both areas were positive for MDM2 and CDK4 by immunohistochemistry. The diagnosis of the RP sarcoma was revised to dedifferentiated LPS. CONCLUSIONS There were no previous case reports of synchronous occurrence of GC with LPS in the English and Japanese literature. GC and LPS pose challenging problems in their diagnoses, staging, and treatments when they occur synchronously or metachronously.

Dedifferentiated Liposarcoma: A Comprehensive Historical Review With Proposed Evidence-based Guidelines Regarding a Diagnosis in Need of Further Clarification

Among all sarcoma types, liposarcoma is the most common sarcoma that develops "dedifferentiation." Since its initial description by Dr Harry Evans, the spectrum of what is now acceptably included under the rubric of "dedifferentiated liposarcoma" (DL) has expanded, sometimes supported by cytogenetic and molecular advances. Similarly, the range of morphologic appearances considered to represent the precursor of DL, atypical lipomatous tumor (ALT)/well-differentiated liposarcoma, also has broadened, not uncommonly creating variants with significant, almost indistinguishable, morphologic overlap with occasional forms of DL, especially problematic in small biopsy specimens. More specifically, the precise criteria separating cellular forms of ALT from what some consider "low-grade" variants of DL remains controversial and inconsistently applied, even among individual pathologists within institutions. For this separation, the only objective and reproducible criteria historically shown to accurately predict a statistically significant difference in prognosis and survival is mitotic rate, alone or incorporated into a histologic grade [eg, Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC)], consistently identifying a higher grade neoplasm capable of metastases. While DL may have a better prognosis than other nonmyoid adult pleomorphic soft tissue sarcomas, definitive conclusions are difficult to establish due to nonuniform criteria for staging and establishing tumor size/volume of the high-grade component, compounded by variable definitions and thresholds for rendering the diagnosis of DL. If appropriate therapeutic approaches are to be applied to DL, there needs to uniform agreement regarding the histologic definition, grading, and staging of DL. Herein, is a comprehensive historical perspective on DL and ALT/well-differentiated liposarcoma, seeking to provide insights, updates, and a proposal for uniform, evidence-based guidelines.

Diagnostic Utility Of Fish For MDM2 In Adipocytic Neoplasms

BACKGROUND

The 2013 World Health Organization (WHO) classification of soft tissue and bone tumours recognizes benign entities such as lipoma and four major liposarcoma subtypes: atypical lipomatous tumour/well differentiated liposarcomas (ALT/WDL), dedifferentiated liposarcomas (DDL), myxoid liposarcoma and pleomorphic liposarcoma. This classification of atypical and malignant adipocytic tumours has evolved significantly over the past few decades owing to contributions from cytogenetics, molecular genetics and Immunohistochemical correlates. Most ALT/WDLs can be diagnosed on histology; however, some of the biopsies may be underdiagnosed due to focal atypia or limited nature of tissue for the biopsy. Fluorescence in situ hybridization (FISH) for MDM2 (located at 12q14-15) gene amplification has emerged as gold standard for diagnosis in cases with limiting histological factors.

METHODS

We studied MDM2 amplification by FISH in 55 such problematic adipocytic tumours with overlapping morphological features and a retrospective analysis was made against their corresponding histological features.

RESULTS

MDM2 amplification correctly identified 11 of 17 ALT/WDLs (64.71% concordance) and 8 of 10 Lipomas (80% concordance). We were able to differentiate liposarcomas from other high grade sarcomatous lesions and sub-classified these lesions into pleomorphic and dedifferentiated types.

CONCLUSIONS

FISH for MDM2 amplification should be used as a gold standard in adjunction with morphology and immunohistochemistry for problematic adipocytic neoplasms.

Clinical Application of Chromosome Microarray Analysis in the Diagnosis of Lipomatous Tumors

Well-differentiated liposarcoma/atypical lipomatous tumor (WDLS/ALT) and dedifferentiated liposarcoma (DDLS) have characteristic supernumerary ring and giant marker chromosomes involving the chromosomal region 12q13-15 which contains MDM2 (12q15), CDK4 (12q14.1), HMGA2 (12q14.3), YEATS4 (12q15), CPM (12q15), and FRS2 (12q15). Detecting MDM2 amplification by fluorescence in situ hybridization (FISH) is considered to be the gold standard for the diagnosis of WDLS/ALT and DDLS. In this study, formalin fixed paraffin embedded clinical specimens (16 liposarcomas and 19 benign lipomatous tumors) were used to detect MDM2 amplification and other chromosomal alterations in WDLS/ALT and DDLS by single nucleotide polymorphism-based chromosome microarray (CMA). All 16 liposarcomas showed MDM2 amplification with a MDM2/cep12 ratio from 2.4 to 8.4 by CMA. Ten (62.5%) of these cases had CDK4/cep12 ratio ≥2.0. All the cases without CDK4 amplification were from the thigh. The MDM2/cep12 ratio of all the benign lipomatous tumors (19/19) was within the normal limits. Twenty-one of the 35 benign lipomatous tumors and liposarcomas were also tested for MDM2 amplification by FISH. All the FISH results were consistent with the CMA results (100%). Along with MDM2 amplification, all 16 liposarcomas (100%) also showed amplification of YEATS4, CPM and FRS2. Only 11 of 16 (69%) cases showed HMGA2 amplification. In conclusion, this study demonstrated that CMA on routine formalin fixed paraffin embedded tissue is a sensitive and specific clinical test for detection of MDM2 gene amplification. Moreover, CMA allows simultaneous detection of genomic changes of interest including CDK4 and others, which provides enriched information for diagnosing lipomatous tumors.

The utility of fluorescence in situ hybridization (FISH) in determining DNA damage-inducible transcript 3 (DDIT3) amplification in dedifferentiated liposarcomas - an important diagnostic pitfall

BACKGROUND AND OBJECTIVE

Dedifferentiated liposarcoma (DDLPS) is characterized by non-lipogenic sarcoma fields coexisting with adipocyte-rich well-differentiated areas. Amplification of the 12q13-15 region includes the MDM2 and DDIT3 genes. MDM2 amplification is considered a genetic hallmark of DDLPS, while DDIT3 is typically rearranged in myxoid liposarcoma. Recent studies showed that DDIT3 amplification is associated with myxoid liposarcoma-like (LPS-like) morphology in DDLPS. Our study aimed to evaluate the status of MDM2 and DDIT3 by FISH in DDLPS and correlate it with MLPS-like features.

MATERIAL AND METHODS

Six patients with MLPS-like morphology DDLPS were investigated pathologically, immunohistochemically, and genetically. The control groups of patients with classical DDLPS morphology and well-differentiated liposarcoma (WDLPS) were established and molecularly assessed as well. Fluorescence in situ hybridization (FISH) used in routine diagnostics was performed to determine the status of MDM2 and DDIT3 genes.

RESULTS

The patient's mean age was 64 (range from 43 to 85 years) with a 5:4 male to female ratio. Tumors were localized retroperitoneally (15) and extra-retroperitoneally (3). All cases demonstrated amplification of the 12q15 region containing MDM2 gene and co-amplification of the 5' DDIT3 FISH Probe representing DDIT3 telomeric tag. However, we did not find the relation of myxoid LPS-like morphology with DDIT3 amplification as previously reported.

CONCLUSIONS

The biopsy material from DDLPS with myxoid areas can be misclassified as myxoid liposarcoma. Indeed, according to the histological image, DDIT3 status may be evaluated first. In these cases, we show that the DDIT3 telomeric tag amplification assessed by FISH, is a common, nonspecific feature, which is also found in classical DDLPS and WDLPS. Therefore, we believe that co-amplification of DDIT3 and MDM2 may be considered a spectrum of the 12q13-15 region amplification due to the specification of FISH methodology.

Development and validation of a novel prognostic model for long-term overall survival in liposarcoma patients: a population-based study

Objective

To construct and validate a clinically accurate and histology-specific nomogram to predict overall survival (OS) among liposarcoma (LPS) patients.

Methods

We retrospectively screened eligible patients with LPS diagnosed between 2004 and 2015 from the Surveillance, Epidemiology, and End Results database. We screened independent predictors for the nomogram using univariate and multivariate analyses. We then evaluated the prognostic accuracy of the nomogram by receiver operating characteristic (ROC) curve analysis and Harrell’s concordance index. The prognostic performances of the nomogram and the American Joint Committee on Cancer (AJCC) seventh edition staging system were compared using integrated discrimination improvement (IDI), net reclassification improvement (NRI), and decision curve analyses (DCA).

Results

A novel nomogram was developed using independent prognostic variables, which exhibited excellent predictive performances for 3- and 5-year OS according to ROC curves. The C-index proved that the proposed nomogram had better prognostic accuracy for LPS than the traditional AJCC system, while the NRI, IDI, and DCA of the nomogram indicated better clinical net benefit.

Conclusions

The proposed nomogram can predict 3- and 5-year OS of LPS patients with reliable accuracy and may thus help clinicians to develop appropriate clinical therapies and counseling strategies to prolong the life expectancy of these patients.

Hypopharyngeal spindle cell lipoma: A case report and review of literature

RATIONALE

Spindle cell lipoma is a rare, uncommon type of benign lipomatous tumor, a distinct group of lipomas composed of mature adipocytes, uniform spindle cells, and multinucleated giant cells associated with ropey collagen. Immunohistochemically, spindle cell lipoma is characterized by the diffuse expression of CD34.

PATIENT CONCERNS

We present a rare case of a 56-year-old man who complained of vomiting out of a smooth and giant mass in the oral cavity provoked by an intra-abdominal pressure increase. Oral examination revealed an elongated mass protruding from the mouth. Computed tomography of the patient showed a mass from left pyriform to oral cavity, with 2.38 × 2.78 × 16.86 cm in size. The flexible fiberscope showed that the pedicle of the elongated mass originated from the posterior wall of the hypopharynx, corresponding to the left pyriform fossa.

DIAGNOSIS

Histopathologically, the tumor was mainly composed of hyperplastic adipocytes, admixed with small blood vessels, and scattered inside adipose tissue spindle cells. The immunohistochemical profile revealed positivity of spindle cells for CD34, negativity for S100, and low proliferation with Ki67, which confirmed the diagnosis of spindle cell lipoma and revealed its benign behavior.

INTERVENTIONS

The patient underwent hypopharyngeal mass resection using transoral suspension laryngoscopy.

OUTCOMES

No recurrence was found after 5 months of follow-up.

LESSONS

Spindle cell lipoma is difficult to diagnose early because of slow growth and subtle symptomatology. This entity should be differentiated from several benign or malignant subtypes of lipomas, including liposarcomas. In this case, the spindle cell lipoma is large and originates from the hypopharynx, which is a rare entity and presents with atypical symptoms. This case gave rise to further studies on the clinical and pathologic characteristics of this tumor in the future.

Changes of the hepatic subcapsular blood flow in a case of high-grade retroperitoneal liposarcoma: what to expect?

Changes of the hepatic subcapsular blood flow with the early appearance of hypervascularity near the falciform ligament are rare radiologic findings. They present most frequently in cases of superior vena cava (SVC) obstruction and are related to the recruitment of the cavo-mammary-phrenic-hepatic-capsule-portal and the cavo-superficial-umbilical-portal pathways. We present the case of a 52-year-old female patient with an highly aggressive retroperitoneal liposarcoma with SVC obstruction caused by external compression due to a mediastinal metastatic mass. The patient exhibited no symptoms of SVC obstruction due to the collateral cavo-portal pathways.

Retroperitoneal liposarcoma in older person - a rare case report

Retroperitoneal sarcoma is relatively uncommon, constituting only 10-15 percent of all soft tissue sarcomas. The most common histologic types of RPS are liposarcoma and leiomyosarcoma. Retroperitoneal sarcoma is classified based on the amount of lipid inside the cells, the mucoid lipid and the degree of cell differentiation. It is classified into the well-differentiated, myxoid, round cell, pleomorphic and dedifferentiated types and the commonest is the pleomorphic type. Dedifferentiated liposarcomas are defined by the presence of sharply demarcated regions of non-lipogenic sarcomatous tissue within a well-differentiated tumor. This type has a vague prognosis compared to other types of sarcoma and making the histological diagnosis can be difficult. Dedifferentiated liposarcoma commonly develops in the retroperitoneum, limbs, testis, and spermatic cord. Retro peritoneal sarcoma typically produces few symptoms until they are large enough to compress or invade surrounding structures. Most tumors are already large and locally advanced at the time they are first detected. Here, we reported a case that came to medical attention as an incidentally discovered large abdominal mass in an asymptomatic or minimally symptomatic, later the mass was successfully removed and free from symptoms.

Dedifferentiated Liposarcoma of the Descending Colon: A Case Report and Review of the Literature

Dedifferentiated liposarcomas are rare; localization of these tumors in the descending colon is extremely uncommon. We describe the case of a 75-year-old man with a dedifferentiated liposarcoma originating from the descending colon that manifested as partial bowel obstruction. The very uncommon presentation of this rare disease contributed to a challenging diagnostic process. The patient was successfully treated by surgical resection of the mass through left hemicolectomy. Although exceptionally unusual, soft tissue sarcomas should be considered in the differential diagnosis for bowel obstruction. Currently, radical resection of the mass is considered to be the first-line treatment.

Primary retroperitoneal tumor during pregnancy: Case report and review of the literature

OBJECTIVE

To report the case of a pregnant patient diagnosed with a primary retroperitoneal tumor and to conduct a review of the literature pertaining to the diagnosis, treatment and maternal-fetal prognosis of this disease condition during pregnancy.

METHODS

A 19-year-old patient who presented with a retroperitoneal tumor identified on ultrasound. The results of the percutaneous biopsy showed a benign tumor. A healthy neonate was delivered by cesarean section. Surgical resection was performed four months later, and histopathology showed a mature cystic teratoma. A search was conduced in the Medline via PubMed, Lilacs, SciELO and ScienceDirect databases using the terms "pregnancy," "neoplasms," and "retroperitoneal neoplasms," including case reports and case series of retroperitoneal tumors during pregnancy. Diagnosis, treatment and maternal-fetal prognosis were identified.

RESULTS

Overall, 1658 titles were identified. Of these, 34 case reports and 1 case series met the inclusion criteria. Of the cases, 62.9 % were benign. Diagnosis was made as an incidental finding in 63 % of cases, and 77 % of the masses were identified on ultrasound. Percutaneous biopsy was used in 8 % of cases, including the case reported here. Surgical treatment was used in 88 % of cases usually after delivery. Maternal mortality occurred in 8.5 % of cases. Fetal prognosis was good in 65 % of the pregnancies.

CONCLUSIONS

Despite being frequently benign, retroperitoneal tumors during gestation have a reserved maternal and fetal prognosis in a substantial number of cases. There is a need to assess the risks and benefits of percutaneous biopsy.

Dysplastic lipoma: potential diagnostic pitfall of using MDM2 RNA in situ hybridization to distinguish between lipoma and atypical lipomatous tumor

The distinction between lipoma and atypical lipomatous tumor can be challenging in some cases. While detection of MDM2 gene amplification via fluorescence in situ hybridization (FISH) has been well established as a diagnostic tool to distinguish atypical lipomatous tumor and well-differentiated liposarcoma from benign mimics, MDM2 RNA in situ hybridization (RNA-ISH) has recently been proposed as an alternative diagnostic assay. During clinical workup for lipomatous tumors using MDM2 RNA-ISH, we noticed several dysplastic lipomas that were positive for MDM2 RNA-ISH but negative for MDM2 amplification by FISH. In this study, we examined a series of 11 dysplastic lipomas, all confirmed to be negative for MDM2 amplification by FISH. Positive MDM2 RNA-ISH was noted in 10 (91%) dysplastic lipomas. Single-nucleotide polymorphism array on one dysplastic lipoma identified the presence of homozygous deletion of 13q, including the RB1 gene locus with no evidence of MDM2 copy number gain. Our findings on the discordance between MDM2 FISH and MDM2 RNA-ISH highlight the potential utility and pitfalls of using MDM2 RNA-ISH in the distinction of atypical lipomatous tumor and related liposarcomas from dysplastic lipoma.