Squamous cell carcinoma of the breast: a case report
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Squamous cells are normally not found inside the breast, so a primary squamous cell carcinoma of the breast is an exceptional phenomenon. There is a possible explanation for these findings.
A 72-year-old woman presented with a breast abnormality suspected for breast carcinoma. After the operation the pathological examination revealed a primary squamous cell carcinoma of the breast.
The presentation of squamous cell carcinoma could be similar to that of an adenocarcinoma. However, a squamous cell carcinoma of the breast could also develop from a complicated breast cyst or abscess. Therefore, pathological examination of these apparent benign abnormalities is mandatory.
KeywordsSquamous Cell Carcinoma Sentinel Node Breast Carcinoma Pectoralis Major Muscle Primary Squamous Cell Carcinoma
Squamous cell carcinoma is a well known malignancy of the skin and other organs surrounded with squamous cells such as the esophagus and the anus. Squamous cell carcinoma of the breast is very rare. It is important to discriminate this entity from malignancies of the skin of the breast or metastasis of a squamous cell carcinoma somewhere else in the body. In the literature only some small series are reported [1, 2, 3]. Reported incidences of primary squamous cell carcinoma of the breast vary between 0,1% to less than 0,04% of all breast carcinomas [1, 2, 3]. We report a case of primary squamous cell carcinoma of the breast presenting as a usual breast carcinoma. However, in the literature there are examples of less typical presentations, for example starting as an abscess .
A 72 years old white woman presented at the specialized outpatient clinic for breast diseases in the Deventer Hospital in Deventer, The Netherlands. Two weeks earlier, she had discovered a local swelling in her right breast, located behind the nipple. There was no retracted nipple, nor excretion from the nipple. The skin had been red for a while, but this had disappeared spontaneously. The woman was postmenopausal, had given birth to 4 children to whom she had breastfed two. Her family history is relevant for breast cancer, her daughter had breast cancer when she was thirty-five years old. The patient history mentioned a cholecystectomy, hysterectomy and appendectomy and hypertension and atrial fibrillation. She had used some medication against hypertension, an anticoagulant and a tranquilizer.
The case was discussed in the multidisciplinary oncology conference. The decision was made to treat this patient according to the Dutch national guidelines for adjuvant treatment with breast carcinoma, just like an adenocarcinoma. Patient was thus started on hormonal therapy: intitially tamoxifen 20 mg daily for two and a half year and an aromatase inhibitor hereafter for the same period. The patient had no other complaints or signs of another tumour.
A year after the operation there were no indications for relapse nor for metastasis or a skin tumor. The tamoxifen was replaced by an aromatase inhibitor because of side-effects, mostly nausea.
Almost two years after the operation she visited the outpatient medical oncology clinic because of fatigue, anorexia and weight loss. Laboratory investigation showed hypercalcemia. Further evaluation with bone scintigraphy and an ultrasound of the liver showed both, bone and liver metastases. The metastatic disease in the lever was proven by FNA. She was briefly admitted to the clinical ward and was transferred to a hospice facility, where she died shortly afterwards.
Primary squamous cell carcinoma of the breast is very rare. It is called primary pure squamous cell carcinoma when the malignant cells are all of the squamous cell type, there is no relation with the skin and if there is no indication for a primary location somewhere else in the body [4, 5]. It is noteworthy to distinguish this type from mixed tumours, where some patches of squamous cells can be found in adenocarcinoma of the breast and from metastasis of squamous cell carcinoma of an origin somewhere else. The etiology and pathogenesis of squamous cell carcinoma of the breast is still unclear. It has been suggested that it may be a very extreme form of squamous cell metaplasia, developing into an adenocarcinoma. This could also explain the mixed forms . Moreover, squamous cell metaplasia is also seen in cysts, chronic inflammations, abscesses and adenofibromas. If these disorders may evolve into carcinomas, this may explain the occurrence of primary squamous cell carcinoma. This hypothesis is further supported by many cases, where primary squamous cell carcinoma is reported after its initial appearance as a benign disorder (abscess or after implantation of a breast prosthesis or after radiation therapy) [2, 3, 5, 7, 8, 9]. In our case, however, there was no such pre-existent abnormality. Nonetheless, she did report some inflammation before her presentation at our clinic. In the literature this type of breast carcinoma occurs merely in elderly women. In addition to a presentation with inflammation, the average size of the tumour is larger than adenocarcinoma of the breast [1, 2, 4]. There are no typical findings on the mammogram. Ultrasound may show a complicated cyst or an inflammatory process. A biopsy should be obtained. In our case, fine-needle aspiration showed malignant cells. The conclusion of the report, adenocarcinoma, was incorrect. In retrospection, it was not justified to draw that conclusion. In one case a correct diagnosis was made on the basis of FNA alone .
Squamous cell carcinomas are reported to result in less lymphatic spread than adenocarcinomas. In 10–30% of cases there is lymph node infiltration at the time of surgery [1, 2]. In contrast, about 30% of the patients will develop distant metastasis. Squamous cell carcinomas are generally hormone receptor negative [1, 2, 3, 4, 5]. It is recommended to give patients similar adjuvant therapy but the radiosensitivity of squamous cell carcinomas is uncertain. The five year survival is 67% in a small retrospective series of eleven patients .
Whether investigations, such as PET scans, in search of distant metastases or a primary squamous tumour site should be performed is still a matter of debate . In our patient, further investigation was initially unwarranted because we had no suspicion that the estrogen positive breast tumour was a distant metastasis of an unknown primary squamous site.
Primary squamous cell carcinoma of the breast is rare. Its existence and possible evolution of an apparently benign disorder underlines the importance of pathological examination of complicated cysts and breast abscesses.
Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
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