Dermatofibromas with Aberrant Expression of CD34 Protein: A Systematic Review and a Reappraisal of Clinicopathological Features and Histogenesis

Background: Dermatofibromas (DFs) are benign fibrohistiocytic lesions that usually do not express CD34 protein. This study aimed to analyze the literature concerning the immunohistological and ultrastructural features of DFs. It also related these features to the histogenesis of these lesions. Methods: This study included a PubMed literature search for studies addressing the clinicopathological, ultrastructural, and immunohistochemical features of DFs. It also presented some current cases of CD34-negative DFs and a subset of these lesions with aberrant expression of this protein. Results: Analysis of the PubMed literature revealed that DFs with an aberrant expression of CD34 are rare tumors that commonly affect the extremities of adult females. Separating these tumors from dermatofibrosarcoma protuberans (DFSP, CD34-positive tumors) requires using a large panel of immunostains. Ultrastructurally, DFs are composed of diverse cell types, including cells with histiocytic, myofibroblastic, and fibroblastic features. An analysis of the DFs described by this study revealed that cases with an aberrant expression of CD34 protein had slightly high mean age and male sex predominance when compared to CD34-negative cases. The former commonly affected the extremities. There was no evidence of local recurrence or distant metastasis on follow-up. Conclusions: DFs have the potential to express CD34 protein, defining a rare aberrant phenotype, which was not associated with any differences in the outcome as compared to CD34-negative DFs

Dermatofibromas with Aberrant Expression of CD34 Protein: A Systematic Review and a Reappraisal of Clinicopathological Features and Histogenesis

Background: Dermatofibromas (DFs) are benign fibrohistiocytic lesions that usually do not express CD34 protein. This study aimed to analyze the literature concerning the immunohistological and ultrastructural features of DFs. It also related these features to the histogenesis of these lesions. Methods: This study included a PubMed literature search for studies addressing the clinicopathological, ultrastructural, and immunohistochemical features of DFs. It also presented some current cases of CD34-negative DFs and a subset of these lesions with aberrant expression of this protein. Results: Analysis of the PubMed literature revealed that DFs with an aberrant expression of CD34 are rare tumors that commonly affect the extremities of adult females. Separating these tumors from dermatofibrosarcoma protuberans (DFSP, CD34-positive tumors) requires using a large panel of immunostains. Ultrastructurally, DFs are composed of diverse cell types, including cells with histiocytic, myofibroblastic, and fibroblastic features. An analysis of the DFs described by this study revealed that cases with an aberrant expression of CD34 protein had slightly high mean age and male sex predominance when compared to CD34-negative cases. The former commonly affected the extremities. There was no evidence of local recurrence or distant metastasis on follow-up. Conclusions: DFs have the potential to express CD34 protein, defining a rare aberrant phenotype, which was not associated with any differences in the outcome as compared to CD34-negative DFs

Membranoproliferative Glomerulonephritis Type I Associated with Intravenous Immunoglobulin Administration Arising in a Child with X-Linked Agammaglobulinemia: A Case Report and a Reappraisal

In 1952, X-linked agammaglobulinemia (XLA) was discovered as a rare inherited disorder. It markedly compromises the ability of the body to combat infectious microorganisms. Membranoproliferative glomerulonephritis (MPGN) Type I is characterized by subendothelial immune complex deposits. Patients with XLA can rarely develop immune-complex-induced diseases. Here, we report a case of MPGN Type I in a 12-year-old male patient with a past and family history of XLA. The patient presented with fever, productive cough, vomiting, and lower limb edema. Clinical and radiological examinations established a diagnosis of bronchopneumonia. The laboratory findings revealed proteinuria and hematuria, and a renal biopsy was performed. The histological examination of this biopsy revealed mesangial hypercellularity and thickened basement membranes. Immunofluorescence studies showed mesangiocapillary staining for Complement 3 and Immunoglobulin (Ig) G and, to a lesser extent, for IgA, IgM, and Complement 1q. Ultrastructural studies revealed partly thick, double-contoured glomerular basement membranes, glomerular endothelial cells with swollen cell bodies, and podocytes with effaced foot processes. Small subendothelial and mesangial eosinophilic deposits were identified. The diagnosis of MPGN type I was established. The patient was started on prednisolone. To the best of our knowledge, this is a rare case of MPGN Type I in a patient with XLA. The pathogenetic mechanisms underlying the development of MPGN Type I were not apparent in our patient. However, residual humoral immunity may play a role in the development of MPGN