Granular Cell Tumor

Questions and Answers

What is the characteristic histological feature of the most well-known variant of malignant peripheral nerve sheath tumor?

Presence of mucin-producing glands

Lack of immunoreactivity for myoglobin

Presence of rhabdomyosarcomatous differentiation (correct)

Absence of necrotic areas

Which immunohistochemical marker is strongly positive in epithelioid malignant peripheral nerve sheath tumor?

Myoglobin

Desmin

S-100 protein (correct)

Cytokeratin

What is the term used to describe a malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation?

Neurofibroma

Epithelioid MPNST

Malignant triton tumor (correct)

Angiosarcoma

What is the significance of recognizing areas of MPNST in a tumor with divergent differentiation?

It is essential for making a diagnosis of malignant triton tumor Signup and view all the answers

What is a differential diagnosis to consider in a tumor with divergent differentiation, if areas of MPNST are not recognizable?

Rhabdomyosarcoma Signup and view all the answers

What is a histological feature of epithelioid malignant peripheral nerve sheath tumor?

Presence of epithelioid cells Signup and view all the answers

What is a characteristic feature of malignant peripheral nerve sheath tumor with angiosarcomatous differentiation?

Presence of endothelial cells Signup and view all the answers

What is a prognostic factor to consider in a patient with malignant peripheral nerve sheath tumor?

History of type 1 neurofibromatosis Signup and view all the answers

What is a characteristic feature of psammomatous melanotic schwannoma?

Presence of melanin pigmentation and psammoma bodies Signup and view all the answers

Which of the following is a differential diagnosis for melanotic schwannoma?

Low-grade MPNST Signup and view all the answers

What is a characteristic location for schwannomas with a microcystic/reticular appearance?

Visceral locations, particularly the gastrointestinal tract Signup and view all the answers

What is a rare feature of otherwise typical schwannomas or those with epithelioid features?

Foci of small, round hyperchromatic cells forming rosettes Signup and view all the answers

What is the prognosis of psammomatous melanotic schwannoma?

It is a low-grade malignancy with a tendency for local recurrence and ability to metastasize Signup and view all the answers

What is a characteristic feature of the cells in a granular cell tumor?

Innumerable fine cytoplasmic granules and scattered larger eosinophilic globules Signup and view all the answers

Which of the following immunohistochemical markers is typically positive in granular cell tumors?

S-100 protein Signup and view all the answers

Which complex is psammomatous melanotic schwannoma a component of?

Carney complex Signup and view all the answers

What is a characteristic of schwannoma by electron microscopy?

Features of schwannian differentiation with a continuous and often reduplicated basal lamina Signup and view all the answers

What is the gross appearance of a neurofibroma?

Gelatinous Signup and view all the answers

Which of the following is a differential diagnosis for granular cell tumors?

All of the above Signup and view all the answers

What is a characteristic feature of neurofibroma?

Fibrous and vascular elements Signup and view all the answers

What is the significance of S-100 protein positivity in granular cell tumors?

It is a useful marker for distinguishing granular cell tumors from other tumors Signup and view all the answers

What is the term for the morphology of some granular cell tumors that have focal granular changes?

Granular cell change Signup and view all the answers

What is the name of the condition associated with plexiform neurofibromas?

Neurofibromatosis type 1 Signup and view all the answers

Study Notes

Differentiation in Malignant Peripheral Nerve Sheath Tumors

Malignant peripheral nerve sheath tumors can have divergent differentiation, such as angiosarcomatous and mucin-producing glands
Rhabdomyosarcomatous differentiation is characterized by the presence of rhabdomyosarcoma-like cells
This variant is often referred to as a malignant triton tumor
Diagnosis requires the presence of areas of recognizable malignant peripheral nerve sheath tumor

Epithelioid Malignant Peripheral Nerve Sheath Tumors

Epithelioid malignant peripheral nerve sheath tumors exhibit strong S-100 protein immunoreactivity
They can have a lipoblastic component, accompanied by cells with signet ring–like features
Some epithelioid schwannomas can contain foci of small, round, hyperchromatic Schwann cells with scanty cytoplasm, simulating neuroblastoma

Psammomatous Melanotic Schwannoma

Psammomatous melanotic schwannoma is a distinctive type of peripheral nerve sheath tumor
It occurs as a component of the Carney complex
It is characterized microscopically by the presence of melanin pigmentation and the deposition of psammoma bodies
It is regarded as a low-grade malignancy due to its tendency for local recurrence and ability to metastasize