Usefulness of immunohistochemistry in delineating renal spindle cell tumours. A retrospective study of 31 cases.
OBJECTIVE
To assess the usefulness of immunohistochemistry in delineating tumour diagnoses on a series of morphologically diagnosed renal spindle cell tumours (RSCTs).


RESULTS
Formalin-fixed paraffin-embedded tissues from 31 morphologically diagnosed tumours were reinterpreted in light of newly obtained immunohistochemical information. By morphology, six had originally been classified as sarcomatoid carcinoma, five as spindle cell tumour (NOS), four as sarcoma (NOS), three as leiomyoma, three as leiomyosarcoma, and one each as fibrous polyp, hamartoma, neurilemmoma, mesoblastic nephroma, medullary fibroma, angiomyolipoma, haemangiopericytoma, malignant rhabdoid tumour, malignant Triton tumour, and carcinosarcoma. The application of immunohistochemistry verified the original diagnosis in 18 cases (18/31, 58%), confirming the diagnosis of sarcomatoid renal carcinoma (4/6), leiomyoma (2/3), leiomyosarcoma (3/3), sarcoma (NOS) (2/4), carcinosarcoma (1/1), malignant rhabdoid tumour (1/1), malignant Triton tumour (1/1), fibrous polyp (1/1), mesoblastic nephroma (1/1), hamartoma (1/1), and angiomyolipoma (1/1). Different tumour designations were suggested in 13 cases (13/31, 42%), including carcinosarcoma, sarcoma (NOS), leiomyosarcoma, solitary fibrous tumour, monomorphic/biphasic angiomyolipoma, endometrial stromal tumour, and congenital mesoblastic nephroma.


CONCLUSIONS
Our data indicate that although morphology is most important in formulating the initial differential diagnosis, the addition of immunohistochemistry is vital in arriving at the correct classification of RSCTs.
Wang
J
J
Division of Pathology and Laboratory Medicine, Loma Linda University Medical Center, Loma Linda, CA 92354, USA. jwang@ahs.llumc.edu
Weiss
L M
LM
Hu
B
B
Chu
P
P
Zuppan
C
C
Felix
D
D
Rausei-Mills
V
V
Chase
D R
DR
D000293:Adolescent; D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000145:classification / Q000175:diagnosis / Q000276:immunology / Q000473:pathology*; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D007223:Infant; D007231:Infant, Newborn; D007680:Kidney Neoplasms / Q000145:classification / Q000175:diagnosis / Q000276:immunology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies