Adult-onset multifocal kaposiform hemangioendothelioma in the bone marrow, lung, liver, and brain: a case report

Abstract

Kaposiform hemangioendothelioma (KHE), a rare form of vascular neoplasm, is typically seen in children. In this paper, we report a unique case of KHE replacing bone marrow tissue mimicking myeloproliferative neoplasm with additional involvement in the lung, liver, and brain in a 60-year-old Caucasian woman. The patient was initially seen in the hematology department for the chief complaint of epigastric pain and anemia. Abdominal magnetic resonance imaging (MRI) revealed mild splenomegaly with iron deposition secondary to extramedullary hematopoiesis. Additional workup was inconclusive. Subsequent bone marrow and lung biopsies eventually revealed bone marrow with extensive grade 3 fibrosis and multiple foci of low-grade vasoformative neoplasm in the lung suggestive of KHE. Although rare, KHE can present as an aggressive disease with indolent behavior in adults and can be distinguished from other vascular malignancies based on histopathology and imaging findings.

Keywords: adult; bone marrow; case report; kaposiform hemangioendothelioma; myelofibrosis.

Figure 1

Bone Marrow Biopsies from 2018 and 2020. (A) Bone marrow biopsy from 2018 showing trabecular thickening and increased cellularity. (B) Bone marrow biopsy from 2020 also showing increased cellularity and increased numbers of atypical spindle cells (inset). (C) A reticulin stain showing extensive fibrosis. A negative CD34 immunostain in the atypical spindle cells (inset).

Figure 2

Lung Biopsy. (A) Lung biopsy from 2021 showing focal, well-circumscribed nodules comprised of atypical spindle cells. (B) Plump spindle cells showing slit-like vasoformative channels (arrows). Lung biopsy also showing ERG positive cells (inset) and CD31 (not pictured).

Figure 3

CT scans without contrast and MRI of the tumor lesions. (A, B) Upper left and right images of a CT scan of the abdomen and pelvis showing hypodense tumor lesions in the liver (A) and spleen (B). (C) Lower left image showing a chest CT scan of the lung with innumerable pulmonary nodules seen throughout the lungs. (D) MRI of the brain showing five supratentorial lesions with minimal enhancement within bilateral cerebral hemispheres. The largest lesion found within the superior left parietal lobe measured 2.4 cm in maximal dimension. Findings consistent with multiple intracranial hemorrhagic metastases with surrounding vasogenic edema.

Figure 4

Detailed Timeline of Events. MRI, magnetic resonance imaging; PBS, peripheral blood smear; BMBx, bone marrow biopsy, PET-CT, positron emission tomography scan; CT, computed tomography; Bx, biopsy; KHE, kaposiform hemangioendothelioma; PD, progressive disease. Created with Biorender.com.