Histiocytic Sarcoma

Allison Zwingenberger

University of California Davis

Publication Date: 2010-11-24

History

10 year old female neutered Golden Retriever. Presented for persistent weight loss and disinterest in food.

Question

1. Where is the increased opacity in the thorax located?

   a	Pulmonary, right caudal lung lobe Incorrect. The mass is located more ventrally and cranially.
   b	Pulmonary, right middle lung lobe Correct.
   c	Mediastinal Unlikely, given the position of the opacity lateral to the heart. It does however silhouette with the heart.

Findings

A large, rounded, soft tissue mass is present in the ventral aspect of the right middle lung lobe. The aortic arch is prominent and a rounded, soft tissue bulge is present in the left fifth intercostal space in the region of the main pulmonary artery. There is periarticular remodeling of both shoulder joints and mineralization of the left bicipital annular ligament.

DDx

• histiocytic sarcoma
• primary pulmonary neoplasia

Diagnosis

• histiocytic sarcoma (obtained from fine needle aspirate of cutaneous masses)
• multiple mesenteric masses and enlarged lymph nodes were identified on abdominal ultrasound

Discussion

Histiocytic sarcoma has a prediliction for the right middle lung lobe, and is usually airway associated.