Quiz-summary
0 of 1 questions completed
Questions:
- 1
Information
Presented by Ashley Cimino-Mathews, MD. and prepared by Mohammed Lilo, MD.
Case 1: A 40 year-old male has a neck mass.
You have already completed the quiz before. Hence you can not start it again.
Quiz is loading...
You must sign in or sign up to start the quiz.
You have to finish following quiz, to start this quiz:
Results
Time has elapsed
Categories
- soft tissue 0%
- 1
- Answered
- Review
-
Question 1 of 1
1. Question
Week 608: Case 1
A 40 year-old male has a neck mass
Correct
Answer:Triton tumor
Histology: The tumor consists of a high grade spindle cell lesion arranged in fascicular growth pattern with nuclear hyperchromasia and abundant mitotic figures. Many cells display overt evidence of skeletal muscle differentiation, with bright pink cytoplasm with cross striations. There are separate fragments of disc material (this is taken from the cervical spine), raising the possibility that this lesion arises from or involves the bone or cartilage. By immunohistochemistry, the lesion is positive for desmin and myogenin. Elsewhere in the lesion but not seen in this slide are regions of neurofibroma, which merge with the malignant neoplasm.
Discussion: This lesion is a malignant peripheral nerve sheath tumor (MPNST) with rhabdomyoblastic differentiation, a “Triton tumor.” The presence of an associated an known pre-existing neurofiboma aids in the diagnosis of this lesion. MPNST are the malignant counterpart to benign nerve sheath tumors and may arise de novo or in association with neurofibromas as a part of neurofibromatosis. Conventional MPST are cellular sarcomas comprised of spindled cells with wavy nuclei, tapering ends, and fascicular growth. The cells characteristically condense around hyalizined blood vessels within the neoplasm and may show geographic necrosis similar to that seen in glioblastoma. There are several morphologic varieties of MPNST, including epithelioid and Triton tumor. In the Triton tumor, the MPNSTS shows skeletal muscle differentiation as evidenced by the morphologic features of the cells as well as immunoreactivity for desmin and myogenin. The skeletal muscle differentiation may be focal, or as in this case, diffuse. The differential diagnosis of MPNST includes other sarcomas such as undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma, MFH), pleomorphic liposarcoma, leiomyosarcoma, fibrosarcoma, synovial sarcoma, as well as sarcomatoid carcinoma and melanoma. Conventional MPNST is only focally immunoreactive for S-100, but epithelioid MPNST can be diffusely positive.
References:
1. Cimino-Mathews A. Peripheral nerve sheath tumors. In Surgical Pathology Clinics: Current Concepts in Soft Tissue Pathology. Guest Editor, EA Montgomery. Consulting Editor, J Goldblum. 2011 (4); 761-782.
2. Evans DG, Baser ME, McGaughran J, et al. Malignant peripheral nerve sheath tumours in neurofibromatosis 1. J Med Genet. 2002 May;39(5):311-4.
3. Fisher C. Immunohistochemistry in diagnosis of soft tissue tumours. Histopathology 2011;58(7):1001-1012
4. Wanebo JE, Malik JM, VandenBerg SR, et al. Malignant peripheral nerve sheath tumors. A clinicopathologic study of 28 cases. Cancer 1993;71(4):1247-1253.Incorrect
Answer:Triton tumor
Histology: The tumor consists of a high grade spindle cell lesion arranged in fascicular growth pattern with nuclear hyperchromasia and abundant mitotic figures. Many cells display overt evidence of skeletal muscle differentiation, with bright pink cytoplasm with cross striations. There are separate fragments of disc material (this is taken from the cervical spine), raising the possibility that this lesion arises from or involves the bone or cartilage. By immunohistochemistry, the lesion is positive for desmin and myogenin. Elsewhere in the lesion but not seen in this slide are regions of neurofibroma, which merge with the malignant neoplasm.Discussion: This lesion is a malignant peripheral nerve sheath tumor (MPNST) with rhabdomyoblastic differentiation, a “Triton tumor.” The presence of an associated an known pre-existing neurofiboma aids in the diagnosis of this lesion. MPNST are the malignant counterpart to benign nerve sheath tumors and may arise de novo or in association with neurofibromas as a part of neurofibromatosis. Conventional MPST are cellular sarcomas comprised of spindled cells with wavy nuclei, tapering ends, and fascicular growth. The cells characteristically condense around hyalizined blood vessels within the neoplasm and may show geographic necrosis similar to that seen in glioblastoma. There are several morphologic varieties of MPNST, including epithelioid and Triton tumor. In the Triton tumor, the MPNSTS shows skeletal muscle differentiation as evidenced by the morphologic features of the cells as well as immunoreactivity for desmin and myogenin. The skeletal muscle differentiation may be focal, or as in this case, diffuse. The differential diagnosis of MPNST includes other sarcomas such as undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma, MFH), pleomorphic liposarcoma, leiomyosarcoma, fibrosarcoma, synovial sarcoma, as well as sarcomatoid carcinoma and melanoma. Conventional MPNST is only focally immunoreactive for S-100, but epithelioid MPNST can be diffusely positive.
References:
1. Cimino-Mathews A. Peripheral nerve sheath tumors. In Surgical Pathology Clinics: Current Concepts in Soft Tissue Pathology. Guest Editor, EA Montgomery. Consulting Editor, J Goldblum. 2011 (4); 761-782.
2. Evans DG, Baser ME, McGaughran J, et al. Malignant peripheral nerve sheath tumours in neurofibromatosis 1. J Med Genet. 2002 May;39(5):311-4.
3. Fisher C. Immunohistochemistry in diagnosis of soft tissue tumours. Histopathology 2011;58(7):1001-1012
4. Wanebo JE, Malik JM, VandenBerg SR, et al. Malignant peripheral nerve sheath tumors. A clinicopathologic study of 28 cases. Cancer 1993;71(4):1247-1253.
