p16 immunohistochemistry as an alternative marker to distinguish atypical lipomatous tumor from deep-seated lipoma.

Molecular Diagnostic Pathology Laboratory, Department of Pathology, Memorial Sloan-KatteringCancer Center, 1275 York Avenue, New York, NY 10021, USA.
Applied immunohistochemistry & molecular morphology: AIMM / official publication of the Society for Applied Immunohistochemistry (Impact Factor: 1.63). 09/2008; 17(1):51-6. DOI: 10.1097/PAI.0b013e3181719223
Source: PubMed

ABSTRACT Atypical lipomatous tumor (ALT)/well-differentiated liposarcoma (WDLPS) is a locally aggressive malignant mesenchymal neoplasm, resembling ordinary lipoma in many clinical aspects. This study investigates the value of expression of p16, an important cell cycle regulator, alone or in combination with MDM2, to distinguish the 2 entities. Fifty cases of lipomatous neoplasms, with cytogenetic results, from 45 patients were collected from the archives in Department of Pathology, University of Medicine and Dentistry of New Jersey/New Jersey Medical School during 1998 to 2006. These include 18 cases of deep-seated lipoma, 1 hibernoma, 1 lipoblastoma, and 30 cases of ALT/WDLPS. p16 was detected in 25/30 (83.3%) of ALT/WDLPS, and none (0/18) of the deep-seated lipomas (P<0.0000001, Fisher exact test). MDM2 was detected in 18/30 (60%) of ALT/WDLPS, and was negative in 0/18 of the deep-seated lipomas (P<0.0001, Fisher exact test). Combined together, 27/30 (90%) of ALT/WDLPS showed positive staining of either p16, MDM2, or both, whereas no staining was observed in all the deep-seated lipomas (P<0.0000001, Fisher exact test). The single case of hibernoma and lipoblastoma revealed p16+MDM2- phenotype. These results indicated that p16 is yet another marker which seems to be a valuable marker to differentiate ALT/WDLPS from deep-seated lipomas.

  • [Show abstract] [Hide abstract]
    ABSTRACT: We studied a series of spindle cell lipomas arising in atypical sites and showing unusual morphologic features (which we called atypical spindle cell lipoma) to assess if these lesions have the same chromosomal alterations as classical spindle cell lipoma but different from those found in atypical lipomatous tumor/well-differentiated liposarcoma. We investigated alterations of different genes in the 13q14 region and the amplification status of the MDM2 and CDK4 genes at 12q14-15 by multiplex ligation-dependent probe amplification (MLPA) and fluorescence in situ hybridization (FISH) analysis. In the atypical spindle cell lipomas, MLPA revealed deletions in the two nearest flanking genes of RB1 (ITM2B and RCBTB2) and in multiple important exons of RB1. In contrast, in classical spindle cell lipomas, a less complex loss of RB1 exons was found but no deletion of ITM2B and RCBTB2. Moreover, MLPA identified a deletion of the DLEU1 gene, a finding which has not been reported earlier. We propose an immunohistochemical panel for lipomatous tumors which comprises of MDM2, CDK4, p16, Rb, which we have found useful in discriminating between atypical or classical spindle cell lipomas and other adipocytic neoplasms, especially atypical lipomatous tumor/well-differentiated liposarcoma. Our findings strengthen the link between atypical spindle cell lipoma and classical spindle cell lipoma, and differentiate them from atypical lipomatous tumor/well-differentiated liposarcoma.
    Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 03/2014; DOI:10.1007/s00428-014-1568-8 · 2.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Spindle cell lipoma (SCL) is a rare tumor of soft tissues, and was first described in 1975 by Enzinger and Harvey SCL often occurs in elderly men as a solitary lesion in the posterior neck and back, and less commonly in the oral cavity. SCL of the tongue is relatively uncommon, and only 14 cases have been reported to date. Here, we describe two cases of SCL of the tongue. A 78-year-old male and a 77-year-old female were diagnosed with tongue tumors, and both underwent resection. Histopathological examination of the resected tumors revealed that they consisted of masses of mature fat cells with fibrous bundles accompanied by hyperplasia of spindle cells surrounding the adipose cells. Immunohistochemistry was performed for histological diagnosis. Using immunohistochemical staining, the spindle cells of each tumor were found to be positive for CD34 but negative for S-100. The nuclei of the spindle cells were negative for Rb and STAT6, and CDK4 and MDM2 immunostaining was negative in every tumor cell. In case 2, some spindle cells were positive for p16, but all were completely negative in case 1. Finally, these tumors were diagnosed as SCLs. To make a definitive pathological diagnosis for SCL, a panel of immunohistochemical markers incorporating CD34, S-100, STAT6, Rb, p16, MDM2 and CDK4 is required to avoid confusion with histologic mimics.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Liposarcoma is the most common soft tissue malignant tumor. It mostly arises in the subcutaneous tissue of shoulders, limbs and neck, and retroperitoneal space, but head occurrence is very rare. Atypical lipomatous tumor (ALT) is a well-differentiated liposarcoma (WDLPS) and constitutes 40-45% of all liposarcoma cases. A case of 57-year-old woman with a tumor of the left cheek, causing a discreet face asymmetry is presented. The tumor was soft and caused no tenderness. The patient reported no previous injury of the region. Fine-needle aspiration biopsy (FNAB) revealed atypical cells suspected of liposarcoma. MR examination showed fascicles of adipose tissue, which made the left cheek prominent. The patient was operated under general anaesthesia. Adipose tissue of the left cheek was removed. Postoperative course was uneventful. The final histopathological diagnosis - was atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS). The patient remains under laryngological care. No recurrence of the disease has been observed during the 5 years follow-up.
    Otolaryngologia polska. The Polish otolaryngology 07/2013; 67(4):218-21. DOI:10.1016/j.otpol.2012.06.022