Sajid Mushtaq ( Armed Forces Institute of Pathology, Rawalpindi. )
Iftikhar A. Malik ( Armed Forces Institute of Pathology, Rawalpindi. )
Manzoor Ahmed ( Armed Forces Institute of Pathology, Rawalpindi. )
M. Safdar Khan ( Armed Forces Institute of Pathology, Rawalpindi. )
Amir Hussain Khan ( Armed Forces Institute of Pathology, Rawalpindi. )
Shahid Jamal ( Armed Forces Institute of Pathology, Rawalpindi. )
Fayyaz A. Malik ( Armed Forces Institute of Pathology, Rawalpindi. )
Ki-1 large cell anaplastic lymphoma is a recently described variant of malignant lymphoma. A retrospective study of 1.0 cases of Ki-I lymphoma was carried out at the Armed Forces Institute of Pathology (AFIP) Rawalpindi to document its clinical and morphological features. The morphological features were evaluated by a study of paraffin embedded sections stained with haematoxylin and eosin stains. Immunohistochemical stains for BER-H2 and leucocyte common antigen (LCA) were performed in all cases. The age of the patients ranged from 2 to 60 years and male to female ratio was 2.3:1. Cervical lymphadenopathy was the most common presentation. Histologically, there was a complete effacement of the lymph node architecture in 8 cases. The Reed-Sternberg like cells were seen in 2 and histiocyte like cells in 7 cases. Immunohistochemically all cases were positive for BER-H2. It is suggested that the possibility of Ki-1 lymphoma should be considered in all cases of lymphoma with pleomorphic morphology. (JPMA 44:169,1994).
Ki-1 large cell anaplastic Jymphoma was initially described by Stein and colleagues1 by finding CD 30/Ki-1 antigen. It is composed of pleomorphic neoplastic cells and may be confused with metastatic carcinoma or malignant histiocytosis2. Immunohisto chemistry is essential to confirm the diagnosis. There is no documented report of this type of lymphoma in Pakistan. We report ten cases of Ki-1 lymphoma, diagnosed at the Armed Forces Institute of Pathology (AFJP) Rawalpindi.
Patients and Methods
Ten cases of anaplastic large cell lymphoma were identified in the surgical pathology department of AFIP Rawalpindi during three years period (1990-1992). The biopsy material was fixed in 10% buffered formalin and was processed for paraffin embedding. The routine haematoxylin and eosin stain was done in all and Periodic-acid Schiff (PAS) and reticulin stains in some cases where required. Immunohistochemical stains were done on paraffin embedded tissues. The sections of 5 micrometer thickness were used for staining of BER-H2 (a monoclonal antibody equivalent to Ki-1) and leucocyte common antigen (LCA) in all cases. The stains for epithetial membrane antigen (EMA) were done in only two cases due to short supply of antibodies. Monoclonal antibodies were obtained from Biogenix Laboratories.
Ki-1 large cell lymphoma is a recently described variant of malignant lymphoma This is characterized by the presence of an antigen called Ki-l (CD3O) antigen1. Stein et al.3, reported that Ki-l antibody (CD3O) marked specifically the neoplastic cells of Hodgkin’s disease. Some other workers described unusualana plastic large cell lymphoma in which neoplastic cells express the Hodgkin’s related antigen Ki-11. It is a rate disease that constitutes about 2-7% of the non-Hodgkin’s lymphoma4. There is no conclusive data available regarding the geographical/epidemiological distribution of this disease probably because of its recent recognition as a separate entity. The disease is characterized by a bimodal age distribution with peaks in 3rd and 8th decades4,5. Majority of our cases were in second and third decade of life. This type of lymphoma is more common in males and this was true incases Clinical presentation is variable and commonly affected sites are lymph nodes, skin, bone and gastrointestinal tract4. The bulk of our cases presented with lymphadenopathy and only I case presented with skin rash. The regression of skin lesions and lymphadenopathy is another unusual feature of this lymphoma6, and such was observed. It is because of its pleomorphic appearance on histology, skin distribution and frequent reactivity with EMA that this lymphoma is often misdiagnosed as metastatic carcinoma in lymph nodes, or as malignant histiocytosis; regressing atypical histiocytosis, nodular sclerosing Hodgkin’s disease, sinusoidal large cell lymphoma and lymphomatoid papulosis2,4. Majority (80%) of our cases were initially diagnosed as metastatic carcinomatous deposits in lymph nodes. One case was diagnosed as malignant histiocytosis and another as Hodgkin’s disease. Immunohistochemistry helps greatly in the differential diagnosis of this disease. The Ki-l lymphomas are always positive for BER- H2 and majority are LCA positive but some may be negative, however, EMA is mostly positive. The tumour cells in Ki-l lymphoma normally stain positively for T-cell markets with some cases having B-cell type markers while others may not show any T- or B-cell differentiation (0-phenotype)4,7. All our cases were BER-H2 positive with negative LCA in 2 cases. We could do EMA staining in only 2 cases and both were weakly positive. It can be concluded that a diagnosis of Ki-l large cell lymphoma should be considered in any histologically pleomorphic lymphoma as Ki-l lymphoma can simulate many other disorders. The diagnosis must be confirmed by immunohistochemical studies.
1. Stein, H., Mason, D.Y., Gerdes, JO. et al. The expression of the Hodgkin’s disease associated antigen Ki-1 in reactive and neoplassic lymphoid tissue: evidence that Reed-Sternberg cells and histiocytic malignancies are derived from activated lym¬phoid cells. Blood, 1985;66:848-58.
2. Bsnks, P.M., Metter, J. and Allred, D.C. Anaplastic large cell (Ki-1) lymphosna with lsistiocytic phenotype simulating carcinoma. Am.J.Clin.Pathol., 1 990;94:445-52.
3. Stein, H., Gerdes, J., Schwab, U. et al. Identification of Hodgkin and Sternberg-Reed cells as a unique cell type derived from a newly-detected small cell population. Int.J.Cancer, 1982;30:445-59.
4. Agnarason, BA. and Kadin, ME. Ki-l positive large cell lymphoma, a morphologic and immunologic study of 19 cases. Am.J.Surg. Psthol., 1988; 12:264-74.
5. Kinneyh, M.C., Greec, J.P., Click, A.D. et al. Anaplassic large cell Ki-1 malignant lyrnphoma. Recognition biological and clinical implications. Pathol. Annu., 1991;26: 1-24.
6. Ohshima, K., Kiksschim, M., Mssuda, Y. et al. Genosypic and immunologic analytis of anaplastic large cell lymphoma (ki- 1). Pathol.Res.Pract., 1990; 1869:582-88.