Low Grade Fibromyxoid Sarcoma of the Parotid in a 5-year-old Child

Abstract

Low-grade fibromyxoid sarcoma (LGFMS) is a rare slow-growing malignant tumour with a deceptively benign histologic appearance. It typically involves young or middle-aged adults. These tumours usually occur in the proximal extremities and trunk. Sporadically they may be found in unusual locations leading to diagnostic dilemma. We report a 5year old boy that presented with painless right parotid swelling of 6 weeks duration. There was a 12-week presentation-to-diagnosis delay, due to the initial misdiagnosis as Burkitt's lymphoma that was entertained because of the region involved, rate of progression and endemicity of Burkitt's in our setting. Compromise of the aerodigestive tract was a major challenge, in addition to early recurrence and metastasis. We advocate for high index of suspicion, prompt tissue diagnosis and multidisciplinary intervention for better outcome.

Keywords: Burkkitt's Lymphoma; Child; Evan's Tumour; Fibromyxoid Sarcoma; Multidisciplinary Team; Parotid Tumour.

Figure 1:

A- Swelling in parotid region at presentation B- Intraoral extension within 8weeks. C- Swelling fills the oral cavity within 12 weeks compromising feeding and breathing.

Figure 2:

Patient with feeding gastrostomy and tracheostomy tube in situ.

Figure 3:

MRI showing: a dumbbell shaped expansile irregular mass in the parotid region (A&B). Appears extensive with extension into the oral cavity and upper margin of lesion in close proximity to the brain (C&D). Lesion is inhomogeneous hypo-intense on T1 Weighted image with foci of irregular more hypo-intensity. It is hyper-intensed on T2 Weighted image and enhances moderately with contrast.

Figure 4:

A- H/E x400 Section show: a proliferating sarcomatous tumor disposed in whorled pattern in areas and myxoid in other areas B- H1304-15(MT) X400 section show: Masson's trichrome (MT) stain. A tri-color staining protocol used in histology. Fibromyxoid area appear pale.

Figure 5:

Tumour specimen

Figure 6: