A case study report of denovo lymph node occurance of myeloid sarcoma

Myeloid sarcoma (MS) as a rare localized solid tumor mass consists of myeloblasts or immature myeloid cells was found in an extramedullary site of a 4 year male child who was suffering with fever, abdominal distension since 4 months and swelling of legs from 1month . On examining pallor, bilateral cervical and inguinal lymphadenopathy, bilateral pitting pedal edema, Hepatosplenomegaly & ascites found. On investigation anemia with leukocytosis, thrombocytopenia was found. USG abdomen showed multiple non necrotic lymphnodes. Bone marrow aspiration suggestive of JMML, lymphnode biopsy showed myeloid sarcoma and was confirmed by immune histochemistry (IHC) markers LCA, KP-1(CD68), myeloperoxidase are positive.Immunophenotyping is useful in differentiating myeloid sarcoma from lymphoma and leukaemia. Child was treated with 3/7 regimen of cytoarabinoside, daunorubicin.


Introduction
In world health organization (WHO) 2007 classification of lymphoid and hematopoietic neoplasms has described myeloid sarcoma (MS) as a rare localized solid tumor mass consisting of myeloblasts or immature myeloid cells in an extramedullary site [1]. MS typically occurs in the later decades of life with median age of 56 years; ranging from, 1 month to 89 years [2]. MS may occur as denovo or concurrently with acute myeloid leukemia (AML), myeloproliferative disorder (MPD) or myelodysplastic syndrome (MDS) or relapse of AML [3] or after allogenic stem cell transplantation [4]. MS occur any part of body most commonly involved site are subperiosteal bone structures of the skull, paranasal sinuses, the sternum, ribs, vertebrae and pelvis, lymph nodes and skin .other rare sites reported in the literature include the pancreas, heart, brain, mouth, breast, gastrointestinal and biliary tract, prostate, urinary bladder and gynecologic tract [5]. MS symptoms and signs depend on site of location. Chemotherapy or hematopoietic cell transplantation is often considered the front-line treatment for MS. Case Report A 4 years male child was presented with complaint of fever, abdominal distension since 4 months and swelling of both legs of from 1month. Fever is intermittent, high grade, not associated with chills and rigors. No cold and cough, burning micturition, vomiting, loose watery stools. No past history of congenital heart disease, contact with tuberculosis, recurrent respiratory tract infection, jaundice, connective tissue disorders. Only child was born out of non consanguineous marriage. No similar complaints in family.
Inguinal lymphnode biopsy showed there are few presereved follicles with expansion of inter follicular & parafollicular area, infilterated by medium to large sized cells with irregular nuclei , prominent nucleoli. ImmunoHistochemistry was positive for LCA, KP-1(CD68), myeloperoxidase. Final diagnosis of extramedullary lymphnode manifestion of monocytic type of myeloid sarcoma was made.

Discussion
Myeloid sarcoma is also known as chloroma, granulocytic sarcoma. Clinical presentation depends on the site of involvement. Myeloid sarcomas is found to be one of the condition with incidence as denovo lymphnode manifestation in whom a typical form of AML may occur after an interval of weeks, months or even years. Rarely no leukemia develops.(1.1%), In association with AML, CMPD or MDS (3-9%) manifestation of relapse is found to be in patients previously treated for primary or secondary acute leukemia [6] .
An extramedullary relapse after allogenic stem cell transplantation with interval of 4-56 month (<1%) [7]. No age group is immune; however, Myeloid sarcoma has a predilection for males (male-to-female ratio, 1.1:2. The pathogenesis mechanism of isolated myeloid sarcoma remains unknown. Histopathologically MS classified based on degree of maturation divided into 1. A blastic variant with predominance of myeloblasts.
2. An immature variant with a mix of myeloblasts and promyelocytes. 3. A differentiated variant with promyelocytes and more mature granulocyte.

Conclusion
Denovo lymph node Myeloid sarcoma -is a rare presentation, Diagnosis of it is often missed initial stages of The disease. But immunophenotyping is very useful in establishing diagnosis of this disease.
It needs to be further evaluated by molecular studies for prognosis. And for intensive study AML like therapy is needed.