br Case report A years old man visited our hospital
Case report A 51-years-old man visited our hospital presenting with a palpable mass over the right inguinal area which had persisted for 3 months. This lesion was approximately 3–4 cm, firm and had progressively enlarged. Laboratory data showed no remarkable anomaly except elevated lactate dehydrogenase (265 U/L). The patient denied experiencing any significant weight loss, poor appetite, night sweats, or sustained fever. After discussing his circumstances with the hematologist in our outpatient department, the patient agreed to undergo surgical excision biopsy. Subsequent histological analysis revealed DLBCL and he underwent further computed tomography with contrast, and BM examination for complete staging. The computed tomography showed right lumbar, iliac and right inguinal lymphoadenopathies, and his clinical Ann Arbor staging was designated as stage II. Further BM examination disclosed diffuse proliferation of large atypical CD20-positive lymphoid cells using hematoxylin and eosin staining (Fig. 1) and immune-histochemical stain (Fig. 2). This is compatible with diffuse large B cell lymphoma, and the patient\'s staging was upgraded to stage IV. However, at the low power field of 40X, multiple well-circumscribed telomerase inhibitors of polygonal cells with pale cytoplasm were observed in the bone marrow. At the high power field designation of 200X, these cells were oval to spindle-shaped and contained a moderate amount of pale cytoplasm (Fig. 3), which showed positive for tryptase (Fig. 4) and CD25 (Fig. 5) through immune-histochemical evaluation. The picture was compatible with systemic mastocytosis with associated clonal hematological non-mast cell lineage disease. Thus, the final diagnosis for this male patient was DLBCL, with right lumbar, iliac and right inguinal lymphoadenopathies and BM involvement, Ann Arbor stage IVA, International Prognostic Index 3, coexisting with SM. In March 2013 he began a course of immune chemotherapy with rituximab, cyclophosphamide, vincristine and prednisolone (R–CHOP), which was the standard treatment for DLBCL. The treatment consisting of 6 courses of R–CHOP was completed in September 2013, and a follow-up integrated Positron emission tomography and computerized tomography (PET-CT) scan revealed nearly complete remission of DLBCL. The port-A was removed in April 2015, as scheduled, and the patient was followed-up regularly in the outpatient department presenting in routine stable condition.
Discussion Although mastocytosis is a rare disease, it may occur in any age and its presentation is can vary with age. Cutaneous mastocytosis is most common in children, while SM is usually diagnosed in patients > 20 years of age. According to the WHO classification, the major criterion for SM diagnosis is that multifocal, dense infiltrates of mast cells (≥15 mast cells in aggregates) are detected in sections of bone marrow and/or other extra-cutaneous organs. The other minor criteria for diagnosis are based on either mast cell morphology, genetic mutation at codon 816 of KIT, detection of surface markers of CD2 and/or CD25 or serum total tryptase. Successfully documented diagnosis for SM needs to meet the major criterion and one of minor criteria, or three of minor criteria (Table 1). Recent study revealed mastocytosis was associated with somatic gain-of-function point mutation within KIT tyrosine kinase domain, particularly the D816V mutation and it has been regard as minor criterion for diagnosis, irrespective of WHO SM subtype. Another important approach tool is tryptase, which can be detected in both mast cell or serum, and elevated serum tryptase level > 20 ng/ml; however, this is also regarded as a minor criterion for SM diagnosis in WHO framework. One earlier study disclosed that ASM and SM-AHNMD patients exhibited a higher level of serum tryptase (usually > 200 ng/ml) than those with ISM. Of note, serum tryptase levels are also elevated in certain hematological diseases, such as acute myeloid leukemia, chronic myeloid leukemia and myelodysplastic syndrome. BM examination is undoubtedly most essential for the study of both SM and lymphoma for staging, because BM is almost universally involved in adult mastocytosis. Berezowska et al had reviewed 59 adults with initial presentation of skin mastocytosis and 57 (96%) of whom were eventually diagnosed with SM by further bone marrow examination. In that study, 42 (71%) subjects met the major criterion and one minor criterion, while the other 15 (25%) met three of the minor criteria.In addition, BM examination also allows for detection of a second hematological neoplasm. In this case presentation, diagnosis of SM was obtained from BM examination for DLBCL staging and involving SM-AHMND.