Primary spindle cell sarcoma of the breast masquerading as necrotizing fasciitis
A 45-year-old healthy Caucasian female patient presented in the emergency department with sudden onset of left breast erythema. On examination, she had an oedematous, tender, erythematous left breast with areas of blistering, epidermolysis and necrosis. Observations demonstrated systemic inflammatory response syndrome with tachycardia, pyrexia and hypotension. Investigations demonstrated raised inflammatory markers, electrolyte abnormalities and severe anaemia. An ultrasound scan revealed the presence of gas and fluid-filled pockets.\nThe Laboratory Risk Indicator for Necrotising Fasciitis score can be utilized to risk stratify patients presenting with signs of cellulitis to determine the likelihood of necrotizing fasciitis. A score >6 of 13 indicates that necrotizing fasciitis should be seriously considered. In this case, a score of 8 was allocated for serum sodium of 126 mmol/l, haemoglobin of 6.6 g/dl and C-reactive protein of 306.7 mg/l. Her other biochemical markers were normal, including serum creatinine of 68 µmol/l, plasma glucose of 8.8 mmol/l and a leukocyte count of 11.5 × 109/l. A provisional diagnosis of necrotizing fasciitis was made, and the patient was referred to the breast surgeons. She was taken to the theatre immediately, where she underwent a mastectomy.\nThe histopathology demonstrated that the breast was partially replaced by a partly cystic and partly solid necrotic lesion. The cystic cavity contained blood clots. A microscopic examination showed an atypical undifferentiated spindle cell lesion with a fascicular architecture, pleomorphism and marked mitotic activity with areas of ulceration and necrosis (Figs and ). The initial set of immunostains performed showed that tumour cells were negative for cytokeratins (Fig. ), S100 and LCA. The tumour cells showed diffuse and strong vimentin positivity (Fig. ). Further immunocytochemical labelling showed weak expression of CD99, patchy strong expression of CD10 and patchy weak expression of smooth muscle actin. Cytokeratins (CAM 5.2) and EMA were expressed and there was no tumour-specific expression of CD34, desmin or myogenin. Fluorescent In-situ hybridization analysis failed to demonstrate evidence of a t(x:18) translocation using the LYS-SYT break apart probe. The diagnosis of a Grade 3 undifferentiated spindle cell sarcoma was made and although the tumour was reported to have a clear resection margin (5 mm) in most areas, the presence of necrosis and granulation tissue reaching the deep margin made the status of the margin uncertain.\nStaging computed tomography scan demonstrated left axillary lymphadenopathy and a small left-sided basal effusion. Following discussion of the case at the multidisciplinary meeting, radical completion mastectomy was recommended. In addition, she underwent adjuvant radiotherapy. Reconstruction was with a split thickness skin graft by the plastic surgery team prior to her radiotherapy treatment (Fig. ).