The differential diagnosis is fairly broad and includes phlegmon/abscess, nerve sheath tumor, synovial sarcoma, fibrous histiocytoma (benign, malignant and angiomatoid
forms), angiosarcoma, and fibromatosis.
Constrictive and complex arteriolar lesions in pulmonary arterial hypertension--plexiform (network of vascular channels lined by endothelial cells with a core of myofibroblasts or less well differentiated cells) and dilation lesion (thin-wall, veinlike vessels distal to plexiform lesion with angiomatoid
features) (hematoxylin-eosin, original magnification X80).
Definitive diagnosis of MAE is based on morphological and immunohistochemical findings that differentiate it from other vascular lesions of the spleen, including splenic hemangioma, lymphangioma, angiosarcoma, littoral cell angioma, hamartoma, and sclerosing angiomatoid
nodular transformation (SANT) of the spleen.
Several histologic variants are reported, with myxoid, angiomatoid
, giant cell, and inflammatory types most common in this location.
When arterial branch dilatation affects a cluster of vessels, it is termed an angiomatoid
lesion Grade V (hallmark Plexiform Plexus of lesion) proliferation capillary-like channels within a dilated arterial branch of the thick-walled parent artery that yields a glomoid appearance to the vessel + overlying thrombotic material Grade VI (rare) Vascular necrosis + Fibrinoid necrosis inflammation of smooth muscle in the vascular media + a necrotizing arteritis with either lymphocytes or neutrophils
The different variants of MFH include storiform, pleomorphic, myxoid, inflammatory, giant cell and angiomatoid
ABH has to be differentiated from blood dyscrasias (thrombocytopenia, von Willebrand's disease, other coagulopathies and leukemia), immunobullous disorders (bullous pemphigoid, linear IgA disease, cicatricial pemphigoid, and dermatitis herpetiformis), angiomatoid
lesions in Osler-Rendu-Weber syndrome.
Structural changes include medial hypertophy, intimal proliferation, fibrosis, luminal occlusion, angiomatoid
changes and eventially fibrinoid necrosis.
However, epitheloid findings observed in some angiosarcomas and immunohistochemically determined cytokeratin and epithelial membrane antigen positivity may cause difficulty in differentiation from angiomatoid
Variants of Spitz nevus Variants Reference Angiomatoid
Spitz nevus (a) 2, 3 Atypical pigmented spindle cell nevus (b) 4, 5 Atypical Spitz nevus (c) 4, 5 Desmoplastic Spitz nevus (d) 6, 7 Hyalinizing Spitz nevus (e) 1 Malignant Spitz nevus (f) 5, 8 Pagetoid Spitz nevus 5, 9 Pigmented spindle cell nevus 4, 10, 11 Recurrent Spitz nevus 12 Spitz nevus with florid pseudoepithelial 13 hyperplasia Spitz nevus with halo phenomenon 14 Tubular epithelioid cell nevus (g) 15 (a) Several investigators consider angiomatoid
Spitz nevus to be a variant of desmoplastic Spitz nevus.
Splenic EBV-associated IPT should also be differentiated from inflammatory myofibroblastic tumor (IMT), Hodgkin lymphoma, interdigitating dendritic cell sarcoma, conventional FDC sarcoma, sclerosing angiomatoid
nodular transformation of the spleen (SANT), lymphoplasmacytic lymphoma, EBV-positive lymphoproliferative disorder, and EBV-associated smooth muscle tumor.
The following conditions may show characteristics similar to that of LCA and when appropriate, should be included in the differential diagnosis: hemangioma, hamartoma, sclerosing angiomatoid
nodular transformation (SANT), hemangioendothelioma, hemangiopericytoma, angiosarcoma, lymphoma, and metastatic disease.