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Department of Otolaryngology/ Head and Neck Surgery St George’s Hospital NHS Trust London, UK

Correspondence to: A. Andrews, 2 Woodridings Close, Hatch End, Middlesex, HA5 4RF, UK Email: abiandrews@yahoo.co.uk

Development of a lipoma within the subcutaneous tissues of a trapezius myocutaneous flap is very rare. This is more so when it occurs after surgery for a head and neck cancer. In the case report described, it masqueraded as tumour recurrence causing significant anxiety. To the best of our knowledge this is a previously unreported ‘complication’

Keywords: Myocutaneous flap, neoplasm, lipoma, neck Surg J R Coll Surg Edinb Irel., 1 December 2004, 355-357

An 80-year-old lady presented to the Head and Neck Clinic with a three-week history of a rapidly growing mass (3.5 x 4.5cm) behind the lobule of the right ear with no clinical involvement of the facial nerve. Computerised tomography (CT) demonstrated this mass to be solid and arising centrally within the parotid gland, extending into the deep lobe of the gland medial to the posterior margin of the mandible. There was no cervical lymphadenopathy clinically or radiologically. Fine needle aspiration (FNA) confirmed the malignant nature of the tumour. The overlying skin was stretched and felt to be clinically involved. Therefore, right parotidectomy with removal of the overlying skin, partial pinnectomy (lobule, external auditory canal and tragal cartilage) was performed with a selective neck dissection (levels 1-3). The defect was covered with a trapezius myocutaneous pedicled flap. The histological appearances were of a poorly differentiated squamous cell carcinoma. The overlying cutis and perichondrium of tragus were involved. The anterior resection stromal margin was involved. There was no lymph node involvement. She received 60 Gray in 30 fractions of post-operative radiotherapy. The patient continued with two-monthly follow-up in the combined Head and Neck Clinic. Her post-operative facial nerve partial paralysis was seen to recover and she remained disease-free. Twenty months after the completion of radiotherapy, a 2cm x 2cm mass was noticed in the upper region of the myocutaneous flap reconstruction raising concern of tumour recurrence. Fine needle aspiration cytology, however, revealed fibroadipose tissue only. The CT appearances were suggestive of a lipoma (Figure 1) and CT-guided FNA of the mass also suggested this diagnosis, showing necrotic fatty material only. The patient was then reassured and routine follow-up resumed. The mass has remained static in size in the last 12 months.

Figure 1: An unusual ovoid shaped lesion (1.2 x 1.6 x 1.9cm) is seen lying superiorly within a trapezius myocutaneous flap. It has a well defined wall and Hounsefield measurement of its centre reveals it to be filled with fat.

Tumour recurrence within a myocutaneuos flap is well documented.^1-3 Different parts of the flap, including the flap pedicle, have been reported to be involved.^4-6 Detection of recurrence may be delayed or complicated because normal anatomical landmarks are obscured by muscle bulk. Hidden recurrence may be as high as 5% and is more likely in irradiated patients.³

Second primary tumours arising within a flap are rare. There are six separate reports in the literature of cutaneous squamous cell carcinoma arising in myocutaneous flaps used to reconstruct the pharynx.^4-6 However, benign primary soft tissue tumours, to the best of our knowledge, have not been previously described. Lipomas generally represent the most common soft tissue tumours. Most lipomas become apparent in patients between the ages of 40 and 60 years. Superficial lipomas arise most commonly in the regions of the upper back and neck, shoulder and abdomen.¹² The majority of myocutaneous flaps used in head and neck reconstruction have donor sites arising from these regions. Our patient had a trapezius myocutaneous flap.

In summary, we present an unusual case of a primary benign soft tissue tumour (lipoma), masquerading as a tumour recurrence in a myocutaneous flap. Such benign neoplastic tumours should, therefore, be considered in the differential diagnoses of a mass arising within myocutaneous flaps, since making an accurate diagnosis avoids considerable patient and surgeon anxiety.

1. Biller HF, Baek SM, Lawson W, Krespi YP, Blaugrund SM. Pectoralis major myocutaneous island flap in head and neck surgery: Analysis of complications in 42 cases. Arch Otolaryngol 1981; 107(1):23-26.

2. Maisel RH, Liston SL, Adams GL. Complications of pectoralis myocutaneous flaps. Laryngoscope 1983; 93(7):928-30.

3. Ossoff RH, Wurster CF, Berktold RE, Krespi YP, Sisson GA. Complications after pectoralis major myocutaneous flap reconstruction of head and neck defects. Arch Otolaryngol 1983;109(12):812-14.