Proliferating Pilar (Tricholemmal) Cyst/Tumor David Cassarino, MD, PhD Key Facts Terminology Proliferating pilar tumor (PPT), proliferating pilar cyst (PPC), proliferating trichilemmal cyst/tumor Multicystic squamous neoplasm composed of mature keratinocytes lining…
Pilar (Tricholemmal) Cyst Steven D. Billings, MD Key Facts Clinical Issues 90% of pilar cysts present on scalp Microscopic Pathology Circumscribed simple cyst Filled with dense eosinophilic keratin Stratified squamous…
Epidermoid/Epidermal Inclusion Cyst Elsa F. Velazquez, MD Key Facts Etiology/Pathogenesis Infundibular cyst variant Implantation (inclusion) cyst variant Clinical Issues Very common lesions Usually affecting face, neck, and trunk Microscopic Pathology…
Mast Cell Disease Carlos E. Bueso-Ramos, MD, PhD Roberto N. Miranda, MD L. Jeffrey Medeiros, MD Key Facts Clinical Issues Multiple clinical variants; common variants are Cutaneous mastocytosis Indolent systemic…
Follicular Lymphoma Roberto N. Miranda, MD Key Facts Terminology Follicular lymphoma (FL) Etiology/Pathogenesis Bcl-2 overexpression is present in most cases of FL Results from t(14;18)(q32;q21)/IgH–BCL2 Other factors are involved in…
Histiocytic Sarcoma Roberto N. Miranda, MD Key Facts Terminology Malignant neoplasm composed of mature histiocytes Diagnosis based mainly on morphology and immunophenotype Etiology/Pathogenesis Transdifferentiation in subset of cases B-cell lymphoma…
Hairy Cell Leukemia Variant Roberto N. Miranda, MD Key Facts Terminology Hairy cell leukemia variant (HCL-v) Mature B-cell neoplasm involving peripheral blood, bone marrow, and spleen Resembles classical HCL but…
Diffuse Large B-cell Lymphoma Arising in the Spleen Roberto N. Miranda, MD Key Facts Terminology Primary DLBCL of spleen is rare Involvement of splenic hilar lymph nodes and bone marrow…
Splenic Marginal Zone Lymphoma Roberto N. Miranda, MD Key Facts Terminology Splenic marginal zone lymphoma (SMZL), splenic B-cell marginal zone lymphoma (2008 WHO), splenic lymphoma with circulating villous lymphocytes (SLVL)…
Mantle Cell Lymphoma Roberto N. Miranda, MD Key Facts Etiology/Pathogenesis CCND1-IGH/t(11;14)(q13;q32) resulting in Cyclin-D1 overexpression in most cases Clinical Issues MCL is nodal-based disease but extranodal sites of involvement are…
