Source 1: WHO Classification of Skin Tumors
Notes: 4th Edition
Reportability--Skin: Is pseudomyogenic hemangioendothelioma (PMH) reportable with morphology code 9133/3? See Discussion.
According to the literature, PMH is a low-grade malignant vascular neoplasm of different tissue planes including skin and soft tissue. However, the references also state: PMH is a cutaneous tumor that behaves in an indolent fashion. There is no indication that this was a malignant diagnosis.
12/3/18 Foot, left skin lesion, punch biopsy: Superficial squamous epithelium demonstrating hyperkeratosis and fragments of keratin debris, no tumor seen.
Foot, left skin lesion, punch biopsy: Pseudomyogenic (epithelioid sarcoma-like) hemangioendothelioma, see note.
NOTE: The submitted immunohistochemical slides were reviewed. Positive and negative controls reacted appropriately. The tumor cells demonstrate immunoreactivity to CK AE1/AE3 and CK7. The CD31 immunoreactivity described in the report cannot be confirmed as only the positive control is submitted for review. The tumor cells are negative for desmin, CD45, CD68, S-100, CD34, SMA, CD20, and HHV8. The proliferative index via Ki-67 is approximately 10%. The morphology (described below) and immunohistochemistry performed are compatible with a pseudomyogenic hemangioendothelioma.
12/4/18 Final Pathologic Diagnosis: Foot, left bone lesion, biopsy: Pseudomyogenic (epithelioid sarcoma-like) hemangioendothelioma, see note.
Note: The patient's imaging findings were reviewed in conjunction with this case, revealing numerous lytic lesions of the tibia, fibula, talus, tarsal, metatarsal, and phalangeal bones. Additionally, as per the medical record, also reviewed in conjunction with this case, there are lesions of the skin. Thus, an extensive immunohistochemical panel was performed in an attempt to support the morphologic findings in this case, which were morphologically similar to the patient's skin biopsy. The tumor cells demonstrate strong immunoreactivity to pancytokeratin (CK AE1/AE3) and vimentin with moderate immunoreactivity to Fli-1. The tumor cells demonstrate weak immunoreactivity to epithelial membrane antigen. INI-1 is retained. There is focal immunoreactivity to CD31 although this is limited to the edges of the tissue fragments. The tumor cells are negative for HHV-8, CD34, smooth muscle actin, CK8/18, desmin, CD99, and Bcl-2. The combination of morphologic (see below for microscopic description) and immunohistochemical findings are consistent with pseudomyogenic hemangioendothelioma. Fresh tissue was submitted for karyotype analysis at the time of intraoperative consultation; however, it revealed only a normal appearing male karyotype. Thus, molecular confirmation was sought. The original slides and a paraffin block were submitted for FOSB rearrangement analysis, as pseudomyogenic hemangioendothelioma is known to have recurrent rearrangements with FOSB. Additional immunohistochemistry performed at (FACILITY) demonstrating immunoreactivity for ERG, supporting a vascular origin for this neoplasm. Fluorescence in situ hybridization demonstrated that 13% of the cells examined show FOSB rearrangement. While this FISH probe is for investigational purposes, the above findings support the diagnosis of pseudomyogenic hemangioendothelioma.
Do not report PMH. The WHO Classification of Skin Tumors lists pseudomyogenic hemangioendothelioma as a borderline malignancy (9138/1). Borderline malignancies of the skin are not reportable.