Epithelioid Kaposi Sarcoma: A New Histological Variant

Diagnostically Challenging Multifocal Penile Epithelioid Hemangioma Successfully Treated With Doxorubicin Hydrochloride

ABSTRACT

Epithelioid hemangioma (EH), also known as angiolymphoid hyperplasia with eosinophilia, is an unusual vascular proliferation that tends to manifest in the head and neck region. Its occurrence on the penis is rare, with only scarce reported cases in the literature. The histopathological examination of this condition poses a challenge because it shares similarities with other entities, such as epithelioid hemangioendothelioma, epithelioid angiosarcoma, cutaneous epithelioid angiomatous nodule, or Kaposi sarcoma (KS). The infrequency of EH in penile locations underscores the need for accurate diagnostic differentiation and tailored treatment strategies for this atypical presentation. This case report highlights a rare instance of multifocal penile EH. The patient's lesions exhibited distinctive histopathologic features, with extensive eosinophilic infiltration, presence of necrosis, and infiltration to subcutaneous fat. The patient was treated with doxorubicin, a chemotherapy drug, with a very good response. This successful therapeutic outcome underscores the potential efficacy of doxorubicin in the management of multifocal penile EH. The comprehensive analysis of this case contributes to our understanding of the clinical presentation, histopathologic features, and treatment modalities for this rare penile tumor, providing valuable insights for future clinical considerations.

Angiosarcoma-like Kaposi Sarcoma: A Distinctive Histomorphologic Variant Representing an Important Diagnostic Pitfall

Kaposi sarcoma (KS) is a rare low-grade angioproliferative neoplasm associated with human herpesvirus 8 (HHV-8) infection with multiple clinical subtypes and varying histopathologic patterns. Histologically, many different variants of KS have been reported, yet all can be difficult to recognize and must be differentiated from other vascular tumors. In this report, we studied fourteen cases of a newly described variant of KS reminiscent of a well-differentiated angiosarcoma (angiosarcoma-like KS). All cases showed a diffuse, ill-defined infiltrative dermal-based lesion composed of numerous anastomosing vascular channels of varying caliber lined by a single layer of endothelium with minimal pleomorphism. The vascular proliferation ramified through the dermis and dissected the collagen bundles along with infiltration into the subcutaneous fat and around skin appendages. All cases showed expression of vascular markers (CD31, CD34, and ERG) and were positive for HHV-8. None showed the classic histopathology associated with KS. Without clinical guidance these tumors can be difficult to recognize as KS, creating significant diagnostic challenges. Our study expands on a rare histologic variant of KS that ought to be considered in the differential diagnosis of any cutaneous well-differentiated angiosarcoma. Awareness of this variant of KS is of important for proper diagnosis and management of these patients; thus, careful attention to the histomorphology and clinical history can help lead the pathologist to the correct diagnosis.

Epithelioid and clear-cell variant of Kaposi sarcoma: A rare histopathologic subtype

Kaposi sarcoma is a malignant vascular tumor consisting of multiple clinical subtypes and varying histopathologic patterns. We report a case of a 53-year-old African-American male with HIV/AIDS who presented multiple times with skin nodules, pain, and edema in his lower extremities, secondary to recurrent Kaposi sarcoma. The patient was treated with two courses of liposomal doxorubicin with improvement, but his symptoms recurred a third time. A biopsy specimen of one of the nodules showed prominent neoplastic cells of epithelioid morphology, some with clear-cell change, appearing to form rudimentary vessels in the superficial dermis. Further inspection of the deeper dermis revealed more classic findings of Kaposi sarcoma, including admixed spindle cells, poorly defined vessels, scattered apoptotic bodies, entrapped collagen bundles, and extravasated erythrocytes. Both the epithelioid and classic portions of the neoplasm stained positive for CD31 and human herpesvirus 8, supporting a diagnosis of Kaposi sarcoma. Prior to this case, the epithelioid variant of Kaposi sarcoma has been reported only twice in the literature. Recognizing this rare histopathologic variant of Kaposi sarcoma among its other histopathologic patterns may assist in accurate and expedient diagnosis of this well-recognized disease.