Histiocytic Sarcoma: Clinical Features and Outcomes of Patients Treated at a Tertiary Cancer Care Center

Abstract

Histiocytic sarcoma (HS) is an extremely rare histiocytic disorder of unknown etiology. It is not a true sarcoma and is named so, due to the pathological resemblance to mature histiocytes. The clinical presentation of HS is diverse and is related to the involved organs. Due to its aggressive nature, with poor prognosis and lack of a standard treatment regimen of choice, its diagnosis and management pose a challenge to the clinician. Limited literature is available on the management of this entity. Here, we report four patients with HS, diagnosed over 15 years in a tertiary cancer center, with varied clinical presentation, management, and outcomes. The first patient presented with a localized unresectable esophageal mass. He was treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) combination chemotherapy and attained complete remission. The second patient had a painless mass of the hand, treated with wide excision and adjuvant Radiotherapy. She is disease-free for the past 12 years. The third patient had presented with an anterior mediastinal mass. He had progressive disease on chemotherapy. The fourth patient had multifocal disease with generalized lymphadenopathy. She was treated with CHOP chemotherapy and is now disease-free at 13 months. To summarize, the patients with the localized resectable disease did well, with surgical excision and adjuvant radiotherapy, while patients with the multifocal disease did well on CHOP chemotherapy. The take-home message from this case series is - CHOP off whenever you can and if not give CHOP to chop off the disease.

Keywords: histiocytic sarcoma; multifocal; surgical resection; systemic chemotherapy; unifocal.

Figure 1. Histopathology and immunohistochemistry of patient 1 showing esophageal mass: upper GI endoscopy and biopsy. Histiocytoid tumor cells in an inflammatory background (low-power view).

Figure 2. Histiocytic cells are CD68 positive (IHC, x400).

Figure 3. Histiocytic cells are CD163 positive (IHC, x400).

Figure 4. Histiocytic cells with high MIB%.

Figure 5. Pre-treatment PET-CT scan showing localized, unresectable lower thoracic esophageal mass

Figure 6. Post treatment PET-CT scan showing complete metabolic response