Pure squamous cell carcinoma (SCC), an extremely rare neoplasm, which according to the WHO classification [1
] is listed under metaplastic breast carcinoma. Two variants of SCC are acantholytic variant of a squamous cell carcinoma (AVSCC) characterized by lack of cohesiveness of the tumour cells resulting in a pseudovascular or pseudoglandular appearance [2
] and adenosquamous carcinoma [3
]. The age of patients ranges from 29 to 90 years with a median age of 52 year [4
]. The reported incidence is of 0.1% of all ductal carcinomas [5
]. Here we report a rare case of an acantholytic variant of squamous cell carcinoma, the rarity of which has been documented by Lee et al
] who noted that up to now only nine cases of AVSCC of breast have been reported.
Case history: A-60-year-old woman presented with 7 × 4 cm lump just below the nipple and areola in her right breast which had developed over the previous two months. There was no retraction or discharge from the nipple and the skin over the lump was normal. Two ipsilateral axillary lymph nodes were enlarged. Left breast examination was normal. Her past and family history were not significant. An ultrasound examination revealed solid hypoechogenic masses with complex cystic components. FNAC yielded 7 ml of dirty fluid from the lump. Air-dried smears were prepared from the centrifuged aspirated fluid and stained with haematoxylin and eosin. The stained smears showed individual malignant squamous cells and loosely cohesive clusters of cells. Cells were polygonal in shape with hyperchromatic enlarged nuclei and coarse chromatin. Keratinous debris was present in the background. A differential diagnosis of primary and metastatic squamous cell carcinoma was made. A total body computed tomography (CT) scan and bone scan, carried out to identify other sites of squamous cell carcinoma in the body, were normal. The patient underwent MRM with ipsilateral axillary clearance. Macroscopically the primary tumour was located 0.5 cm below nipple and areola and measured 7 × 4 × 3 cm. A cross section of the mass showed a cystic area with necrosis in the upper portion and a grey white solid area just below it (). Two axillary lymph nodes were isolated. Histopathology showed cells arranged in pseudoglandular pattern, and at places cells were arranged in loose cohesive clusters representing acantholysis (). The cells were polygonal, with nuclear pleomorphism, coarse chromatin and dense eosinophilic cytoplasm. Intermingling stroma had lymphocytic infiltration. There was an associated intraductal component which showed ducts lined by squamous cells with central region of necrosis similar to comedo necrosis. The necrotic component was comprised of keratinous debris (). Extensive sampling of nipple, areola and skin was carried out but these regions were completely free of neoplastic cells. There was no associated invasive ductal carcinoma or any other feature of metaplastic carcinoma. Only one lymph node was metastatic.
Microphotograph of cut section of the mass showing a cystic area with necrosis in upper portion and a grey white solid area just below it (H&E stain).
Figure 2 (a) Microphotograph showing malignant squamous cells in pseudoglandular pattern (H&E stain). (b) Microphotograph showing malignant squamous cells in pseudoglandular pattern (H&E stain). (c) Microphotograph showing acantholysis of squamous (more ...)
Microphotograph showing intraductal component which showed ducts lined by squamous cells with central region of necrosis (H&E stain).