Table of Contents
Definition / general | Etiology | Clinical features | Diagnosis | Prognostic factors | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosisCite this page: Avadhani V. Liposarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pleuraliposarcoma.html. Accessed January 18th, 2021.
Definition / general
- Very rare, < 20 cases reported; more common in extremities and retroperitoneum
- Ages 19 - 80 years, mean age 49 years, usually men
- Usually myxoid subtype
Etiology
- Origin: residual rests of primitive mesenchymal tissue
Clinical features
- Presenting clinical complaints: shortness of breath, cough, pleurisy
Diagnosis
- Distinction of pleural liposarcoma from liposarcomas arising from chest wall or mediastinum requires careful radiographic and surgical evaluation
Prognostic factors
- Difficult to determine due to rarity but positive surgical margins are considered important as in other chest wall sarcomas
Case reports
- 42 year old man with pleural myxoid liposarcoma (J Cardiothorac Surg 2007;2:48)
- 45 year old woman and 67, 73 and 80 year old men with liposarcoma of pleural cavity (Arch Pathol Lab Med 2000;124:699)
- 47 year old man with massive pleural based tumor (Rev Port Pneumol 2011;17:275)
- 56 year old woman with pleural liposarcoma mimicking carcinoma in pleural effusion cytology (Acta Cytol 2010;54:601)
- 58 year old man with liposarcoma of pleural cavity (Thorac Cardiovasc Surg 2008;56:438)
Treatment
- Low grade tumors: complete surgical resection with tumor free margins
- High grade tumors: adjuvant therapy may be considered
Gross description
- Tumor size ranges from 3 cm to greater than 10 cm
- Yellow-gray, rubbery, nodular, lobulated, gelatinous or mucoid
Microscopic (histologic) description
- Most common histologic subtypes: myxoid and well differentiated
- Criteria for a lipoblast:
- Hyperchromatic indented nucleus
- Lipid rich droplets in cytoplasm
- Appropriate histologic background
- Classification:
- Atypical lipomatous tumor / well differentiated liposarcoma (ALN / WDL): predominantly composed of mature fat with a variable number of atypical hyperchromatic spindle cells and multivacuolated lipoblasts
- Subtypes include:
- Lipoma-like
- Sclerosing
- Inflammatory
- Subtypes include:
- Dedifferentiated liposarcoma: atypical lipomatous tumor / well differentiated liposarcoma juxtaposed to high grade nonlipogenic sarcoma (most commonly high grade fibrosarcoma or undifferentiated pleomorphic sarcoma)
- Myxoid liposarcoma: multinodular mass composed of spindle cells or fusiform cells in a myxoid matrix with a delicate plexiform capillary vascular network
- Pleomorphic liposarcoma: areas of undifferentiated pleomorphic sarcoma and pleomorphic lipoblasts
- Spindle cell liposarcoma: very rare
- Atypical lipomatous tumor / well differentiated liposarcoma (ALN / WDL): predominantly composed of mature fat with a variable number of atypical hyperchromatic spindle cells and multivacuolated lipoblasts
Microscopic (histologic) images
Positive stains
Molecular / cytogenetics description
- ALN / WDL are characterized by giant marker and ring chromosomes - amplified sequences of 12q13-15
- MDM2 amplification evaluated by FISH is highly specific and sensitive for ALN / WDL
- Myxoid liposarcomas are characterized by t(12:16)(q13;p11), resulting in fusion of DDIT3 gene on #12 with FUS gene on #16; rare translocation is t(12;22)
Differential diagnosis
- Benign lipomatous lesions: fat atrophy, spindle cell lipoma, lipomatous solitary fibrous tumor
- Metastases
- Myxoid lesions: myxoma, myxoid undifferentiated pleomorphic sarcoma
- Nonlipogenic sarcoma