Immunophenotyping of Tumours

Abstract

Background: Immunophenotyping has added a new dimension to improve the diagnostic accuracy of malignant diseases. The emphasis is on its usefulness in planning and institution of specific therapy besides helping in prognostication.

Methods: The study included 83/1385 biopsies of cancer patients over an 18 month period on which immunohistochemical staining (IHC) with monoclonal antibodies were performed. The technique was used to establish the histogenetic origins/expression of the tumours. The study excluded haematolymphoid malignancies.

Result: Eighty three cases on whom IHC was performed included poorly differentiated tumours (15), metastatic tumours (16), soft tissue tumours (35), central nervous system tumours (9) and miscellaneous (6). Two cases could not be typed. The clinicopathological correlation in terms of the management and the problems related to its misinterpretation are discussed.

Conclusion: Immunophenotyping of tumours in an oncology set up is significant in the 'Final Diagnosis'.

Keywords: Diagnosis; Immunophenotyping; Tumour markers.

Fig. 1

Diagnostic tumour categories for immunophenotyping

Fig. 2

Thymic carcinoma. A. Poorly differentiated tumour composed of large cells in sheets with necrosis (H&E × 4). B & C. Tumour cells positive for epithelial markers (B. cytokeratin (IHC-DAB ×10), C. Epithelial membrane antigen (IHC-DAB ×20). D. Background lymphocytes express leucocyte common antigen (LCA) (IHC-DAB ×10)

Fig. 3

Prostatic adenocarcinoma presenting as a bladder tumour. A. Poorly differentiated tumour in sheets invading bladder muscle (H&E ×20). B. Focally tumour cells show lobular and glandular patterns (H&E × 10). C. Tumour cells positive for prostate specific antigen (PSA) (IHC-DAB × 20)

Fig. 4

Sub-typing of soft tissue tumours

Fig. 5

Rhabdomyosarcoma Right arm: anaplastic variant A. Healed operation scar of tumour resected elsewhere and reported as high grade sarcoma NOS. B. Pleomorphic tumour with spindling and haemangiopericytomatous vasculature (H&E × 4). C. Diffuse vimentin positivity of tumour cells (IHC-DAB ×10). D. Strong desmin positivity of the tumour cells (SMA negative: not in picture) (IHC-DAB ×20)

Fig. 6

Posterior mediastinal mass: Malignant ganglioneuroma. A. Mitotically active acellular, spindle cell tumour suggestive of a malignant nerve sheath tumour (H&E ×20). B. Focal ganglion like cells (H&E ×20). C. Spindle and ganglion cells with S-100 positivity (IHC-DAB ×20). D. The ganglion cells alone stained for neurofilament (Nf) (IHC-DAB ×20)

Fig. 7

MALTOMA thyroid (hemithyroidectomy multinodular goiter) A. Diffuse infiltration by a monotonous small lymphocytic population (H&E ×4). B. Formation of lymphoepithelial lesions in barely perceptible thyroid follicles (H&E ×10). C. Cytokeratin highlights the thyroid follicles (IHC-DAB ×10). D. Leucocyte common antigen positive neoplastic lymphocytes (IHC-DAB ×20)

Fig. 8

Multiple myeloma with generalized lymphadenopathy A. The lymph node was overrun by diffuse sheets of plasma cells (red arrows) leaving residual reactive follicles at the periphery (yellow arrows) (H&E × 10). B. Plasma cells with vesicular nuclei and nucleoli (H&E × 20). C. Plasma cells show EMA cross-reactivity (IHC-DAB ×20). D. Residual lymphocytes express LCA while plasma cells are negative (IHC-DAB ×20)