Thyroid-like Follicular Carcinoma of the Kidney

Definition

A very rare renal tumour morphologically mimicking follicular carcinoma of the thyroid. In chronic pyelonephritis and end stage renal disease, the kidney may take on a thyroid-like appearance. Thyroid-like follicular carcinoma of kidney is the equivalent appearance in a tumour. The follicles contain inspissated material resembling colloid.

Epidemiology

This tumour occurs in adults across a wide age range.

Macroscopic appearance

The tumour is usually small. It is well demarcated with a tan/brown/dark brown cut surface.

Histopathology

There is a fibrous capsule. The tumour consists of microfollicles and macrofollicles containing inspissated colloid-like material. papillary architecture, clear cell change and spindle cells are lacking. There is no necrosis or haemorrhage. Nuclei are generally round, Fuhrman grade 2. Nuclear clearing, grooves and inclusions, as seen in papillary carcinoma of the thyroid, are absent. The mitotic rate is low.

Immunohistochemistry

	AE1/AE3	1/1(intense positivity)1
	CD10	1/1(intense positivity)1, 0/52
	TTF-1	0/11, 0/52
	Thyroglobulin	0/11, 0/52
	35bH11	1/1(focal cytoplasmic)1
	Vimentin	1/1(focal cytoplasmic)1
	CK7	0/11, 1/52
	CK19	0/11
	CK20	0/11
	34bE12	0/11
	CEA	0/11
	EMA	0/11
	CD15	0/11
	Pax2	0/52
	Renal carcinoma marker	0/52
	Kidney-specific cadherin	0/52
	AMACR	0/52
	WT1	0/52
	Vimentin	0/52
	CD56	0/52
	CD57	0/52

Differential diagnosis

Metastatic thyroid follicular carcinoma: positive for thyroglobulin and TTF-1.
Thyroid-like papillary carcinoma of the kidney: shows the cytomorphology of papillary thyroid carcinoma; positive for thyroglobulin and TTF-13.
Metastasis from struma ovarii
Carcinoid tumour; most commonly occurs within horseshoe kidney; positive for chromogranin and synaptophysin

Prognosis

Behaviour is generally indolent. One case metastasised to renal hilar lymph nodes.

References

1 Jung SJ, Chung JI, Park SH, et al. Thyroid follicular carcinoma-like tumor of kidney: a case report with morphologic, immunohistochemical, and genetic analysis. Am J Surg Pathol 2006; 30:411-5

2 Amin MB, Gupta R, Ondrej H, McKenney JK, Michal M, Young AN, et al. Primary thyroid-like follicular carcinoma of the kidney: report of 6 cases of a histologically distinctive adult renal epithelial neoplasm. Am J Surg Pathol. 2009 Mar;33(3):393-400.

3 Angell SK, Pruthi R, Freiha FS. Primary thyroidlike carcinoma of the kidney. Urology. 1996 Oct;48(4):632-5.

This page last revised 11.4.2010.