Extremely Rare Case of Primary Intimal Sarcoma of the Left Atrium Diagnosed During an Examination for Cerebral Hemorrhage in a 24-Year-Old Woman

A previously healthy 24-year-old woman presented with right homonymous hemianopia and dyspnea. Transthoracic echocardiography revealed a large heterogeneous mass in the left atrium (Figure A). Magnetic resonance imaging of the head revealed a mass within the hemorrhagic regions of the left occipital lobes (Figure B). Emergency tumor resection was performed due to the potential risk of hemodynamic compromise.

Figure.

(A) A large tumor mass obstructing the mitral orifice (arrowheads). (B) Fluid-attenuated inversion recovery image of the head, acquired using magnetic resonance imaging. (C) The tumor extended from the left atrium (arrowheads). (D) The split-plane image showed a white, cystic, and necrotic mass with an irregular surface. (E,F) Hematoxylin and eosin stain. (G,H) Immunostained image.

The tumor extended from the posterior wall of the left atrium to the entrance of the right pulmonary vein, and appeared with an irregular surface (Figure C,D). Pathological findings revealed a robust expansion of spindle-shaped cells proliferating densely, with marked nuclear atypia on hematoxylin and eosin staining and ubiquitously located nuclei accompanied by delicate blood vessels (Figure E,F). Immunostaining showed positive results for vimentin and murine double minute 2, confirming cardiac intimal sarcoma (Figure G,H). The patient experienced a deteriorating cerebral hemorrhage postoperatively and underwent a craniotomy to evacuate the hematoma. Based on the same pathological features in the excised lesion, brain metastasis from intimal sarcoma was diagnosed.

Left atrial primary intimal sarcoma is extremely rare, with only sporadic cases reported. Nakagawa et al reported a similar case of left atrial intimal sarcoma and discussed the distribution of primary malignant cardiac tumors.¹ Because cardiac tumors exhibit a specific distribution, understanding the primary tumor site can aid accurate diagnosis.

Reference

• 1.   Nakagawa-Kamiya T, Mori M, Ohira M, Iino K, Kawashiri MA, Takemura H, et al. Intimal sarcoma: An extremely rare case of a left atrial tumor with partial obstruction of the mitral orifice. CASE (Phila) 2021; 5: 93–96.