Cystic Mediastinal Thymic Lymphangioma Mimicking Echinococcal Cyst

Abstract

A n otherwise healthy 24-year-old woman presented to our hospital with 12 months of worsening dyspnea, left-sided pleuritic chest pain, nonproductive cough, and hoarseness. She denied weight changes, hemoptysis, and systemic infectious symptoms, such as fever, chills, and sweats. She was born and raised in a small town near Mexico City, Mexico, where she had frequent exposure to cats and dogs, and to farm animals, such as cows, goats, and sheep. Initial examination revealed an afebrile, hemodynamically stable woman with mild tachypnea and hoarseness. Pulmonary examination was notable for decreased breath sounds over the entire left chest. Computed tomography of her thorax demonstrated a large multicystic mass extending throughout the entire left hemithorax (Figs. 1-3). Given her exposure history and the appearance and location of the cystic mass, a presumptive diagnosis of pulmonary echinococcus was made, and she was started empirically on albendazole. An echinoccoccus IgG was sent, which was negative. She eventually underwent clamshell thoracotomy with intact removal of the cystic mass, which measured 15 cm × 12 cm × 8 cm (Fig. 4). Tissue histology revealed thymus attached to a multilocular cyst lined by CD31 and D2-40 staining cells, consistent with a cystic mediastinal thymic lymphangioma. There were no elements favoring a diagnosis of echinococcus. Lymphangiomas are congenital abnormalities of the lymphatic system 1 and most typically arise in the head/neck and axillary regions, only rarely occurring in the mediastinum. 2 Although the majority of cystic lymphangiomas are diagnosed in children under the age of 5 years, they are rarely incidental findings in adulthood. 3 Furthermore, although most individuals with mediastinal lymphangiomas are asymptomatic, they can present with chest pain, cough, dysphagia, or dyspnea as

The Rarest of Rare Thymic Lesions: A 10-Year Surgical Pathology Experience

“…Other mesenchymal neoplasms of thymic origin are extremely rare and are described in the literature as case reports. These include solitary fibrous tumor [74], lymphangioma [75,76], angiosarcoma [77], gangliocytic paraganglioma [78], and neuroblastic tumors associated with a thymic cyst [79] or with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) [80][81][82].…”