(1,3) Some cells show voluminous eosinophilic cytoplasm with eccentric nuclei, resembling rhabdomyoblasts
. Regardless of the form, the cells typically have a deeply eosinophilic cytoplasm; oval-to-round, bland nuclei with fine chromatin; and variably distinct nucleoli.
: tumor cells with a spindle cell conformation and eosinophilic cytoplasm with striations (red arrows) (H&E 100X).
It was composed of a fascicular proliferation of plump spindle cells and epithelioid cells with prominent nucleoli and brightly eosinophilic cytoplasm, mimicking rhabdomyoblasts
The presence of cartilage in MMMT is considered a favorable prognostic factor.8 Uterine sarcoma accounts for 3-5% of all corpus uteri malignancies; undifferentiated uterine sarcomas arise from the endometrium or myometrium, lacking any resemblance to normal endometrium and may show heterologous stromal elements in the form of cartilage, bone or rhabdomyoblasts
.9 In our case the hyaline cartilage nodules were mostly located deep in the myometrium, close to the serosal surface and adjacent tissue exhibited foci of adenomyosis; the closest differential diagnosis ruminated was adenosarcoma.
Malignant schwannomas may exhibit divergent differentiation into heterologous elements, such as epithelial, cartilaginous, bony, and adipose tissue as well as rhabdomyoblasts
(malignant triton tumor).
(11) Rhabdomyosarcoma usually affects children and adolescents and the tumors contain characteristic, small, round cells with mitotic activity or have "strap" rhabdomyoblasts
that stain positive for myosin.
Histologically, it bears a close resemblance to various stages in the skeletal muscle embryogenesis: small, round, undifferentiated cells, rhabdomyoblasts
, and myxoid matrix.
In addition, features typical of RMS such as rhabdomyoblasts
and strap cells (embryonal RMS) or alveolar architecture (alveolar RMS) are absent in AFH, which is also negative for specific markers of skeletal muscle differentiation such as myogenin and MyoD1.
We report an instance where rhabdomyoblasts
were seen infiltrating the cerebrospinal fluid (CSF).
The term rhabdoid designates a high-grade tumor cell with abundant eosinophilic cytoplasm and peripherally located nuclei, thus resembling rhabdomyoblasts
(Figure 3, C).
Admixed with this population can be a second cell type of immature rhabdomyoblasts
, (14) usually comprising a small percentage of the total tumor.
Extracellular and Connective Tissue Components Background stroma Neuropil Neuroblastoma Desmoplasia Desmoplastic small cell tumor Myxoid Liposarcoma, embryonal rhabdomyosarcoma Calcifications Neuroblastoma, synovial sarcoma, and MNST Lymphoglandular Non-Hodgkin lymphoma bodies Other elements Neuronal cells Neuroblastoma, ectomesenchymoma Rhabdomyoblasts
Rhabdomyosarcoma Cross-striations Rhabdomyosarcoma Blastema/ Nephroblastoma, pleuropulmonary epithelium blastoma Abbreviation: MNST, malignant nerve sheath tumor.