Paraffin Section Immunophenotype of Cutaneous and Extracutaneous Mast Cell Disease

Abstract

Mast cell disease (MCD) is a rare proliferation that may be easily confused with other hematopoietic tumors. Several paraffin section antibodies immunoreact with mast cells but most are not specific. Tryptase, a specific marker of mast cells, may not be cost-effective to maintain in a laboratory because of the rarity of these lesions. This study was undertaken to assess the immunoreactivity of MCD and attempt to select a limited antibody panel for diagnosing MCD among hematopoietic tumors that morphologically mimic MCD. Immunophenotyping of cutaneous ( 10 cases) and extracutaneous (18 cases) MCD, as well as 94 other hematopoietic neoplasms, was performed on paraffin sections. All cases of MCD showed strong and diffuse positivity for CD68 and tryptase. In the vast majority of the cases, the mast cells were also positive for CD117 (27 of 28) and CD43 (25 of 27). Four cases (40%) of cutaneous MCD demonstrated a subpopulation of mast cells expressing myeloperoxidase (MPX), whereas all extracutaneous MCD were negative for MPX. Two (40%) extramedullary myeloid tumors (EMT) expressed CD43, CD68, CD 117, and MPX, but none expressed tryptase. CD43, CD68, CD117, and tryptase were expressed by 25%, 1%, 15%, and 1%, respectively, of all B-cell lymphoid neoplasms, and none expressed more than one of these four antigens. We conclude that (1) cutaneous MCDs may demonstrate a subpopulation of MPX antigen expressing tumor cells and may be confused with cutaneous involvement by myeloid leukemia if other antibodies are not used; (2) tryptase is the most specific mast cell marker among the antibodies studied; and, (3) the detection of tryptase, together with CD68, CD117, and usually CD43, is unique to MCD among hematopoietic tumors.

Does the Aberrant Expression of CD2 and CD25 by Skin Mast Cells Truly Correlate with Systemic Involvement in Patients Presenting with Mastocytosis in the Skin?

“…In addition, multiple recent and past studies have described the BMMC immunophenotype in detail [11][12][13][14][15][16] . In contrast, little is known about the immunophenotypic profile of skin MCs (sMCs) in patients with mastocytosis [17][18][19][20] . It has been reported that sMCs in mastocytosis patients may coexpress CD25 and CD4 but do not express CD2.…”

“…It has been reported that sMCs in mastocytosis patients may coexpress CD25 and CD4 but do not express CD2. However, it has to be stressed that those studies were based on small groups of patients [17,19,20] . Furthermore, the frequency of CD2 and CD25 expression on sMCs has never been assessed in CM and SM patients, who were diagnosed strictly according to the WHO criteria.…”

Cytodiagnosis of primary lymphoma of bone on fine‐needle aspiration cytology specimens: Review of 25 cases

“…Anti-triptase is the most sensitive and specific marker for the detection of normal and neoplastic mast cells, although anti-triptase reactivity was recently documented in a small cleaved cell lymphoma. 16 It should be noted that mast cells are nearly always positive for CD43, CD68, and CD117 and may show strong reactivity for chloracetate esterase, peroxidase, LCA, and CD11 C . 16 Finally, non-neoplastic lesions, such as osteomyelitis and eosinophilic granuloma, should be considered in the differential diagnosis.…”

“…16 It should be noted that mast cells are nearly always positive for CD43, CD68, and CD117 and may show strong reactivity for chloracetate esterase, peroxidase, LCA, and CD11 C . 16 Finally, non-neoplastic lesions, such as osteomyelitis and eosinophilic granuloma, should be considered in the differential diagnosis. The presence of plasma cells, polymorphonuclear leukocytes (PMNs), small mature lymphocytes, and capillary proliferation favors the diagnosis of osteomyelitis.…”

Rare KIT (CD117) expression in multiple myeloma abrogates the usefulness of imatinib mesylate treatment

“…Yang et al assessed the immunophenotype of cutaneous and extracutaneous mast cell disease on paraffin sections and included in their study, four cases of MM without finding KIT expression [17]. Natkunam et al analyzed the utility of paraffin section immunohistochemistry for KIT in the differential diagnosis of systemic mast cell disease involving the bone marrow and found no expression of KIT in various B-cell lymphomas or plasma cell tumors [8].…”