Comparing Diagnostic Pathway of Two Patients Squamous Cell Carcinoma of the Breast-Favourable Diagnostic Input of CESM

Abstract

A The vast majority of diagnosed squamous cell carcinomas (SCC) are located in the skin, few present within internal structures. Primary breast SCC is a rare unusual tumor, constituting less than 0.1% of all breast carcinomas [1]. Literature reviews mention just about 100 cases of breast SCC to date, but most of the cases are included in a variety of histologic patterns reviews in addition to SCC [2]. Clinical and radiologic appearances of breast SCC are not specific which may cause delays in the correct diagnosis of this rare but quite aggressive type of breast cancer. This article demonstrates two cases of breast SCC diagnosed in Kettering Breast Unit in the last five years and difference in their diagnostic pathway due to the utilisation of contrast enhanced mammography for the second patient. IntroductionThe diagnosis of primary SCC of the breast is made in the absence of an associated primary SCC in a second site and in the absence of skin involvement. Squamous cells are normally not found inside the breast, so a primary squamous cell carcinoma of the breast is an exceptional phenomenon. Reported here are two cases of primary breast SCC presenting initially as complex cysts. However, in the literature there are examples of different presentations, for example starting as an abscess [3]. Case 1A 67 years old lady presented with large, painfull lump in the right axillary tail which appeared suddenly after active prolonged gardening. The first ultrasound scan demonstrated a 6 cm cyst/ fluid collection which was suspected to have been caused by a possible rupture of the big pectoralis muscle. Axilla at the first presentation was unremarkable and blood was drained from suspected haematoma. The haematoma refilled after 7 days and forther aspirate was sent to cytology which demonstrated C5 abnormal cells with squamoid features. The patient was referred for repeat ultrasound and core biopsy. Before biopsy of the bizarre by now looking cystic structure (Figure 1) was again drained and the solid looking component of the walls biopsied. Histology reported features in keeping with poorly differentiated squamous cell carcinoma. A dark lymphnode biopsied at the same time proved to be metastatic.Chest CT with contrast demonstrated a large (8.7cm x 7.9cm x 6.4cm) mixed attenuation partly cystic partly solid mass is seen occupying most of the right axilla and demonstrates patchy enhancement. A couple of sub cm lymph nodes are seen in the vicinity (Figure 2 Cytology report statedThe appearance is unusual. If the cyst was truly in the breast and not in a subcutaneous position, the appearance may indicate squamous metaplasia/neoplasia in a cyst that has arisen in fibrocystic disease.Squamous lined cysts of the breast are rare but have been described.Per MDT decision patient was referred for contrast enhanced spectral mammography (CESM )The low energy image identical to conventional FFDM images (Figure 3) demonstrates a moderate/ low density round structure with partially obscured posterior margin.Figure 4 recombined h...