Some pointers taken from the Dermatopathology RCPA Quality Assurance Programme: 1. Glomus tumour : It can occur in other places other than the nailbed. Other variants may be glomangioma, glomangiomyoma and symplastic glomus tumour. Malignant glomus tumour is a rare entity. A differential is spiradenoma. 2, Fixed drug eruption : Composed of a combination of erythema multiforme -like changes, mixed inflammatory infiltrate, and melanophages in the superficial dermis. Here is a nice explanation on the clinical features . 3. Chondrodermatitis nodularis helicis Painful nodule typically in the upper part of ear in older males. 4. Naevus cell rests in lymph nodes. Apparently it is not that uncommon (22% of lymphadenectomies in a large study). 5. Superficial acral fibromyxoma Circumscribed but non encapsulated lesions, typically at fingers and toes. Strongly CD34 positive. Differentials include: 1. Low grade fibromyxoid sarcoma: Deep soft tissue lesion, ...
( This is another final part of the Sabah lymphoma talk: Part One , Two , Three . ) I. Marginal zone B cell lymphoma Types: Nodal, extranodal, splenic. Immunohistochemically different from mantle cell lymphoma, follicular lymphoma, and small lymphocytic lymphoma. Differential diagnosis: Reactive monocytoid B-cell hyperplasia. Patterns: Diffuse pattern: diffuse sheets of neoplastic cells with effacement of nodal architecture. Nodular pattern: distinct nodules, well-demarcated. Interfollicular pattern: neoplastic cells in interfollicular areas that surround residual germinal centres. Perifollicular pattern: annular distribution of neoplastic cells around the uninvolved normal secondary follicles. Histology: Vague nodules with sclerosed blood vessels. Stromal sclerosis which compartmentalize the small groups of neoplastic cells. Monocytoid / plasmacytoid cells, singly distributed or in clusters. Increased large cells with nuclear pleomorphism (not seen in mantle cell l...