Malignant Fibrous Histiocytoma of the Head and Neck after Radiation Therapy for Squamous Cell Carcinoma

Author: Kevin Sadati, DO, et al

Abstract

A 60-year-old man presented with Malignant Fibrous Histiocytoma (MFH) of the oropharnx extending to nasopharynx and larynx, and causing severe upper airway obstruction requiring emergency tracheotomy. Ten years previously, this patient had undergone right partial glossectomy and segmental mandibulectomy, followed by 50 Gy radiation in 33 sessions for squamous cell carcinoma of the right tongue base. This MFH tumor was so aggressive that changes in its volume were visually distinguishable during physical examination over a two-week hospital stay. Histological evaluation revealed 7 mitotic figures per high power field. Although radiation-induced MFH is rare in the head and neck, recent medical literature reports a rise in its incidence. This has been attributed to increased effectiveness of head and neck cancer therapy, prolonging patients survival. Since MFH is a late complication of irradiation therapy appearing at an average of 10 years following treatment, it is important for physicians treating head and neck cancer to be alert for this long-term post radiation complication and to continue following patients ever after apparent cure of their head and neck neoplasm.

Introduction

Stout and OBrien first described malignant Fibrous Histiocytoma (MFH) in 1964 under the name malignant fibrous xanthoma. (1) This aggressive and high-grade sarcoma is found most commonly in adults. (2) Ionizing radiation, which is an important modality of treatment for head and neck cancer such as squamous cell carcinoma, has been identified as a factor in transformation of soft tissue cells to MFH. (3) The tumor occurs most often in the soft tissues of the extremities and retroperitoneum, and this tumor has been considered rare in the head and neck. (4) The cumulative incidence of sarcoma after radiation therapy ranges from 0.03%-0.3%.

(5) However, a higher incidence of 1%-3% has been reported recently in a post-radiated head and neck cancer patients. (6) The rise in incidence is likely due to increased effectiveness of cancer therapy and consequent prolonged survival. (7) Therefore, it is important for surgeons treating head and neck cancer to be cognizant of this long term post-radiation complication and to continue following these patients.

Case Report

A 60-year-old man presented with a one-month history of progressively worsening dysphonia and dyspnea, which required an emergency tracheotomy to establish an airway.

In 1992, he had undergone right partial glossectomy and segmental mandibulectomy for squamous cell carcinoma of the right tongue base followed by 50 Gy of radiation in 33 sessions at another institution.

CT scan of neck demonstrated a bulky tumor extending from the nasopharynx to the level of true vocal folds, predominately on left side but crossing the midline. The tumor involved the right tongue base and displaced and filled the left pyriform sinus and vallecula. Figures (1 and 2)

At the time of presentation, flexible laryngoscopy revealed a mass occupying his nasopharynx, and direct laryngoscopy under general anesthesia after tracheotomy revealed a left tongue-base tumor with diameter of at least 5 cm occupying the supraglottic region. There was a left neck mass measuring 3cm in diameter. Histological evaluation revealed a moderately cellular spindle cell neoplasm, and marked cytological atypia with multinucleated giant cells, with a high mitotic figure of 7 per high power field. Figures (3 and 4) Necrosis was present and no positive staining for S-100, Desmin, CD117, Factor 8, SMA, CD34, and ALK-1 was present. There was faint positive staining with MYO D1, and a strongly positive stain for CD68. The final pathology diagnosis was malignant fibrous histiocytoma.

The patient and his family declined further treatment. During routine daily physical examination over a two week hospital stay, a substantial volume increase of the oral mass was visualized, highlighting the aggressive nature and rapid growth of MFH.