Several histologic variants are reported, with myxoid, angiomatoid
, giant cell, and inflammatory types most common in this location.
While EWSR1-ATF1 translocation may not entirely define a tumor as CCS (eg, this translocation is also seen in angiomatoid
fibrous histiocytoma), the presence of EWSR1 and ATF1 rearrangements, in conjunction with the morphologic and immunohistochemical features seen in our case, supports a diagnosis of CCS.
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
The subtypes of MFH include storiform ("spoke-like")/pleomorphic, myxoid, giant cell, inflammatory, and 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.
Histologically, undifferentiated thyroid carcinomas show a variety of patterns, from sheet-like, storiform, fascicular, angiomatoid
, and meningothelial to solid, exhibiting extensive lymph-vascular invasion.
They include hemangiomas, littoral cell angiomas, splenic hamartomas (SHs), lymphangiomas, hemangioendotheliomas, angiosarcomas, and Sclerosing Angiomatoid
Nodular Transformation (SANT).
Lesions that may potentially be confused with nodular KS include bacillary angiomatosis, other vascular tumors (eg, spindle cell hemangioma and Kaposiform hemangioendothelioma), fibrohistiocytic tumors (eg, cellular, angiomatoid
, and atypical variants of fibrous histiocytoma, and dermatofibrosarcoma protuberans), resolving dermal fasciitis, spindle cell melanoma, and several other spindle cell mesenchymal neoplasms (eg, cutaneous leiomyosarcoma).
All subtypes of malignant fibrous histiocytoma occur in patients between the ages of 50 and 70 years, with the exception of the angiomatoid
The concept of borderline ovarian carcinoma and the categorization of some soft tissue tumors (such as plexiform fibrohistiocytic tumor, so-called angiomatoid
fibrous histiocytoma, and some types of hemangioendothelioma) are examples of established intermediate borderline diagnostic categories.
For example, the EWSR1-ATF fusion has been identified in 2 histologically and clinically different tumors, clear cell sarcoma and angiomatoid
fibrous histiocytoma, which may be related to the cell of origin of these neoplasms.