Sclerosing paraganglioma

Definition

A tumour of the head and neck or mediastinum arising from paraganglia and showing extensive stromal sclerosis.

Epidemiology

Sclerosing paraganglioma occurs in adults with a female preponderance.

Clinical features

The tumour is generally asymptomatic. One case with tracheal compression presented with dyspnea2.

Macroscopic appearances

The tumour arise in the carotid body, vagal body, parapharyngeal region or mediastinum. They appear partially encapsulated or infiltrative.

Histopathology

There is extensive stromal sclerosis, giving a fallacious impression of malignant infiltration. Within the sclerosis, there are nests and cords of tumour cells. In most cases, the tumour cells have a nested pattern. The tumour cells are variably round, polygonal or spindled. The round cells have abundant cytoplasm. Nuclei are large with prominent nucleoli. Mitoses are sparse and not atypical. There is focal nuclear atypia. Some cases include a peripheral lymphocytic infiltrate. Congo Red stain for amyloid is negative.

Immunohistochemistry

	Chromogranin	positive1, 1/12
	Synaptophysin	positive1, 1/12
	NSE	positive1, 1/12
	S-100	positive in sustentacular cells1, 1/1positive in sustentacular cells2
	Cam5.2	0/12
	AE1/AE3	negative1
	EMA	negative1
	CEA	negative1
	MOC-31	negative1
	SMA	negative1
	CD34	negative1
	CD99	negative1

Differential diagnosis

Metastatic carcinoma: positive for CEA and EMA.
- If clear cell, metastatic renal cell carcinoma.
- If showing Indian file infiltration, metastatic lobular carcinoma of the breast.
Mucoepidermoid carcinoma of salivary glands.
Carcinoma with thymus-like differentiation (CASTLE): positive for cytokeratins and negative for neuroendocrine markers.
Metastatic carcinoid: positive for low MW cytokeratins as well as neuroendocrine markers.
If predominantly spindled:
- solitary fibrous tumour: positive for CD34 and bcl-2 but negative for neuroendocrine markers.
- fibrosarcoma or other sarcoma.
In the mediastinum:
- spindle cell thymoma: the cells are bland and are positive for cytokeratins.
- idiopathic sclerosing mediastinitis.
- nodular sclerosing Hodgkin lymphoma

Prognosis

Some cases show local recurrence after excision.

References

1 Plaza JA, Wakely PE, Jr., Moran C, et al. Sclerosing Paraganglioma: Report of 19 Cases of an Unusual Variant of Neuroendocrine Tumor That May Be Mistaken for an Aggressive Malignant Neoplasm. Am J Surg Pathol 2006; 30:7-12

2 Mukhopadhyay S, Naqvi AH, Su W, et al. Airway-occlusive sclerosing paraganglioma presenting with dyspnea. Am J Surg Pathol 2006; 30:1206-7

This page last revised 23.9.2006.