Mucinous tubular and spindle cell carcinoma, loopoma

Definition

A rare type of renal cell carcinoma composed of a combination of low-grade tubular cuboidal cells and spindle cells in a mucinous stroma. It has been suggested that they are reminiscent of, and derived from, the loop on Henle2 or collecting duct4. Previous reports of collecting duct carcinoma may have contained some such tumours6,7.

Epidemiology

This is a very rare type of renal cell carcinoma. It occurs in adults across a wide age range, with an equal sex incidence2. There is an association with nephrolithiasis2.

Macroscopic appearance

The tumours are circumscribed, with a pushing non-infiltrating margin. They have an "elastic" consistency and contain small foci of haemorrhage and necrosis2.

Histopathology

The tumour is composed of two cell types. The predominant type is a spindle cell with sparse cytoplasm, arranged in fascicles, resembling a low-grade smooth muscle tumour. The second is a small cuboidal cell forming tubular structures and sheets. The tubules are elongated and curving, giving a "fingerprint" appearance. There is a bubbly myxoid stroma which stains intensely with alcian blue. In places, cord of cells float in the abundant stroma, reminiscent extraskeletal myxoid chondrosarcoma . Cysts and papillae are not seen. The cytological appearances are low grade. There is scant cytoplasm and nuclei may protruding into lumina to give a hobnail appearance. Mitoses occur, but are rarely atypical.

One reported case was associated with a conventional renal cell carcinoma2.

 

Immunohistochemistry (with results for papillary renal cell carcinoma for comparison):

 

 

Mucinous tubular and spindle cell carcinoma

Papillary renal cell carcinoma

 
 

AMACR

25/271

19/201

 

Cam5.2

4/112, 4/4 (but weak)3

 

AE1/AE3

11/112, 4/43

 

CK7

 

22/271, 9/92, 4/43

13/201

CK19

0/43

 

CK20

0/43

 

34bE12

4/261, 4/43

3/201

EMA

19/201, 11/112, 4/43

15/171

Vimentin

11/112, 4/43

 

RCC Marker

2/271, negative4

5/201

CD10

4/271

16/201

CD15

0/112, 0/43

 

CD117

1/211

3/171

Ulex europaeus

1/43

 

S-100

the spindle cells are negative, 0/92, 0/43

 

SMA

the spindle cells are negative, 0/112

 

Desmin

the spindle cells are negative, 0/112, 0/43

 

HMB45

0/112

 

Villin

negative4

 

pCEA

0/43

 

MIB1

up to 15/HPF2

 

     

Ultrastructure

The cuboidal cells have short microvilli on the apical borders and tight junctions on the lateral borders. There are no melanosomes or microfilaments2.

Cytogenetics

There are genetic losses involving multiple chromosomes4,5. Fluorescence in situ hybridization detects no von Hippel-Lindau gene deletions on chromosome 3p25, which are characteristic for clear cell renal carcinomas5. The gains in chromosomes 7 and 17 and loss of chromosome Y characteristic of papillary renal cell carcinoma are not see in mucinous tubular and spindle cell carcinoma.

Differential diagnosis

Management

Patients have been treated by simple nephrectomy2.

Prognosis

To date, only two of forty six cases have shown metastases2 and there have been no tumour-related deaths.

References

1 Paner GP, Srigley JR, Radhakrishnan A, et al. Immunohistochemical Analysis of Mucinous Tubular and Spindle Cell Carcinoma and Papillary Renal Cell Carcinoma of the Kidney: Significant Immunophenotypic Overlap Warrants Diagnostic Caution. Am J Surg Pathol 2006; 30:13-19

2 Hes O, Hora M, Perez-Montiel DM, et al. Spindle and cuboidal renal cell carcinoma, a tumour having frequent association with nephrolithiasis: report of 11 cases including a case with hybrid conventional renal cell carcinoma/ spindle and cuboidal renal cell carcinoma components. Histopathology 2002; 41:549-55

3 Parwani AV, Husain AN, Epstein JI, et al. Low-grade myxoid renal epithelial neoplasms with distal nephron differentiation. Hum Pathol 2001; 32:506-12

4 Rakozy C, Schmahl GE, Bogner S, et al. Low-grade tubular-mucinous renal neoplasms: morphologic, immunohistochemical, and genetic features. Mod Pathol 2002; 15:1162-71

5 Weber A, Srigley J,Moch H [Mucinous spindle cell carcinoma of the kidney. A molecular analysis]. Pathologe 2003; 24:453-9

6 MacLennan G, Farrow GM, Bostwick DG: Low-grade collecting duct carcinoma of the kidney: Report of 13 cases of low-grade mucinous tubulocystic renal carcinoma of possible collecting duct origin. Urology 50:679-684, 1997

7 Srigley JR, Eble JN, Grignon DJ, et al: Unusual renal cell carcinoma (RCC) with prominent spindle cell change possibly related to the loop of Henle. Mod Pathol 12:107A, 1999.

 

This page last revised 27.1.2006.

©SMUHT/PW Bishop