Squamous cell carcinoma of breast.
CS Pramesh, P Chaturvedi, AP Saklani, RA Badwe
Breast unit, Department of Surgical Oncology, Tata Memorial Hospital, Parel, Mumbai - 400 012, India. , India
C S Pramesh
Breast unit, Department of Surgical Oncology, Tata Memorial Hospital, Parel, Mumbai - 400 012, India.
|How to cite this article:|
Pramesh C S, Chaturvedi P, Saklani A P, Badwe R A. Squamous cell carcinoma of breast. J Postgrad Med 2001;47:270-1
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Pramesh C S, Chaturvedi P, Saklani A P, Badwe R A. Squamous cell carcinoma of breast. J Postgrad Med [serial online] 2001 [cited 2021 May 14 ];47:270-1
Available from: https://www.jpgmonline.com/text.asp?2001/47/4/270/171
A 47-year-old postmenopausal woman presented with the history of a lump in the upper outer quadrant of left breast for which a lumpectomy had been done. She did not have pain, nipple discharge or skin changes prior to the lumpectomy. She did not have a family history of breast cancer. The histopathology of the lump was an invasive squamous carcinoma of the breast. Examination of her oral cavity and pelvic examination was normal. Her chest radiograph was normal. She did not have any other site of squamous carcinoma. She was subsequently subjected to a mastectomy with axillary clearance. Histopathological examination after exhaustive sampling revealed a moderately differentiated keratinising type of pure squamous carcinoma [Figure:1]. There was no associated in-situ carcinoma and there were no features of glandular differentiation. The axillary lymph nodes did not harbour metastases. The surrounding breast tissue had areas of inflammatory mastitis and ductal hyperplasia. There was no squamous metaplasia at the interface between the tumour and the normal breast parenchyma. The skin and the nipple-areola complex were not involved.
Immunohistochemistry studies showed that it was estrogen receptor negative and progesterone receptor positive. In view of her postmenopausal status and progesterone receptor positivity, she was started on tamoxifen as adjuvant therapy. The patient has been on regular follow-up for the past three years and is disease free.
Malignant breast tumours are broadly divided into epithelial tumours of cells lining ducts and lobules and non-epithelial malignancies of the surrounding stroma. Invasive duct carcinomas are the commonest pathological type accounting for over 70% of invasive breast cancers. Infiltrating lobular, medullary and colloid carcinomas, Paget’s disease and other pure and combined types constitute the remaining 30 per cent. Primary squamous cell carcinoma (SCC) of the breast is rare, and comprises less than 0.1% of invasive cancers. Controversy exists whether a pure form of SCC exists or whether these cases actually represent extreme squamous metaplasia within an adenocarcinoma. The rarity of the condition and the absence of reliable data result in erroneous classification of these tumours.
The rarity of pure squamous cell carcinoma of the breast is brought out by the fact that it is not mentioned in the classification of malignant tumours of the breast in leading textbooks of pathology and oncology. There was not even a single case of pure SCC in a classical review of 1000 cases by Fisher et al. However, squamous metaplasia is the commonest metaplastic variant in human breast cancer and was seen in 36 of the 1000 cases reviewed by Fisher and 16% of typical medullary and 4% of non medullary carcinomas reported by Ridolfi et al. This has been the primary reason behind the difficulty in accurately ascertaining the exact incidence of pure SCC of the breast as many cases initially recorded as SCC have actually been varying degrees of squamous metaplasia in other histological types. These variations range from minute areas of squamous differentiation in a predominant adenocarcinoma to pure squamous carcinoma where no glandular elements can be identified by routine histologic techniques. In Cornog’s review of 24 cases recorded as squamous cell carcinoma of the breast, only three were pure SCC. Two of these apparently arose from epidermal elements and the third from a cystosarcoma phyllodes. All five cases of ‘pure’ squamous cell carcinomas of the breast reported by Woodard et al revealed glandular differentiation on ultrastructural examination.
SCC may originate from the epidermis, the nipple or the malignant transformation of a deep-seated epidermal cyst. Certain criteria need to be fulfilled before the tumour can be classified as a pure SCC of the breast. These are a) no other neoplastic elements are present in the tumour, b) the tumour is independent of adjacent cutaneous structures and c) no other primary epidermoid carcinoma exists in the patient. The cytologic features of these tumours are malignant squamous cells with keratinising cytoplasm, hyperchromatic dense nuclei, coarse chromatin, thickened nuclear membranes, keratin debris and background necrosis. They have to be distinguished from other types of metaplastic mammary carcinoma. Some authors claim that this differentiation may be of mere academic importance and not of much clinical significance., However, others emphasise that this differentiation carries great prognostic significance as they behave more aggressively compared to other metaplastic carcinomas. A careful analysis of all cases of metaplastic carcinomas gives credence to the concept of a disease continuum with varying degrees of squamous metaplasia.
The usual presentation of these tumours is as a firm to hard painless breast lump clinically indistinguishable from other malignant breast lumps. A family history or genetic linkage, though suggested has not been substantiated. Some authors opine that most patients present with advanced disease and that aggressive management is indicated., Other authors claim that there is no effect of squamous differentiation on the clinical behaviour of breast cancer or on survival which is considered to be similar to pure adenocarcinoma of the breast. The rarity of the condition makes it difficult to draw firm conclusions on the course of the disease and the overall prognosis. Mastectomy may be required due to large tumour size. The role of breast conservation in these patients has not been studied. A curious feature of these tumours is the relative rarity of axillary lymph nodal metastases, which is about 10 per cent. This is in contradistinction to squamous cell carcinomas in other sites that metastasise frequently to regional lymph nodes.
These tumours are usually oestrogen and progesterone receptor negative, thereby negating the feasibility of hormonal adjuvant therapy. However, if they are receptor positive, tamoxifen should be the adjuvant therapy of choice. Receptor negative patients may require adjuvant chemotherapy, especially if they are premenopausal. The role of adjuvant radiotherapy has not been extensively studied but may have an important role in management. Careful and accurate classification of these tumours is necessary. A detailed analysis of their biological behaviour and response to therapy is necessary to formulate definite recommendations in managing these patients.
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