Hematoxylin-eosin-stained sections of entities in the differential diagnosis for biphenotypic sinonasal sarcoma, which include synovial sarcoma (A), malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation (malignant triton tumor
; B), glomangiopericytoma (C), and solitary fibrous tumor (D) (original magnifications X200 [A through C] and X100 [D]).
Benign triton tumor
: a rare entity in head and neck region.
The differential diagnosis of a melanotic Schwannoma is made excluding malignant melanoma, pigmented meningioma and neurofibroma, rhabdomyosarcoma, clear-cell sarcoma of soft tissue, melanotic medulloblastoma, ganglioneuroblastoma, ectomesenchymoma (triton tumor
), neurotrophic melanoma, and melanotic neuroendocrine carcinomas and carcinoids .
Summary of reported cases of malignant peripheral nerve sheath tumors of the head and neck (excluding triton tumor
) Author No.
The first patients in the registry include 17 survivors of lymphoma, 8 survivors of sarcoma, 5 survivors of Wilm's tumor, 4 survivors of neuroblastoma, and 1 survivor each of hepatoblastoma, ovarian germ cell tumor, yolk sac carcinoma, and Triton tumor
The malignant triton tumor
is considered when the rhabdomyoblastic differentiation is present, but it occurs in the setting of type 1 neurofibromatosis.
Malignant triton tumor
of the nose and paranasal sinuses:A case study.
Malignant peripheral nerve sheath tumor (MPNST) and malignant triton tumor
(MPNST with rhabdomyoblastic differentiation), potential candidates on morphologic grounds alone, arise often from a large peripheral nerve in patients with known neurofibromatosis.
A true triton tumor
is a malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation, and it is more common than a "benign triton tumor
." (17,18) In most of the earlier case reports, the NMC involved a peripheral nerve, often one of a major nerve trunk.
Malignant schwannomas may exhibit divergent differentiation into heterologous elements, such as epithelial, cartilaginous, bony, and adipose tissue as well as rhabdomyoblasts (malignant triton tumor
One tumor (case 1) was a malignant Triton tumor
, that is, an MPNST with rhabdomyomatous differentiation.