Histologic Patterns of Cutaneous Metastases of Breast Carcinoma: A Clinicopathologic Study of 232 Cases

Centrifugally Spreading Annular Erythema as a Dermatological Indicator of Metastatic Breast Carcinoma

Breast cancer is the leading cause of skin metastasis in women with internal malignancies. This report highlights an atypical case of cutaneous metastasis of breast cancer (CMBC) in a 66-year-old woman. Starting four months before her dermatology consultation, the patient underwent a chemotherapy regimen comprising pertuzumab, trastuzumab, and vinorelbine for right breast cancer, right axillary lymph node enlargement, and bone metastases. After commencing chemotherapy, erythematous macules appeared around her right nipple. Subsequently, the cutaneous lesions developed into annular erythematous patches around her right nipple and began to coalesce and expand to the contralateral breast. A skin biopsy revealed dysplastic cells indicative of metastasis from invasive ductal carcinoma. In addition, lymphovascular tumor cell invasion was noted in the reticular dermis. Based on these clinical progressions and histopathologic findings, a diagnosis of CMBC was made, specifically considering the possibility of inflammatory breast cancer (IBC). The patient continued the same chemotherapy regimen for 17 cycles, which improved the skin lesions, but she succumbed to breast cancer two years later. This case emphasizes the importance of considering CMBC in breast cancer patients with expanding, treatment-resistant thoracic cutaneous lesions, especially in aggressive subtypes like IBC. The diverse presentations of CMBC require thorough histopathological evaluation.

Cutaneous metastases of internal malignancies: a single-institution experience

Aims

Cutaneous metastases of internal malignancies occur in 1–10% of cancer patients. The diagnosis can sometimes be challenging, especially in cases with an unknown primary cancer.

Materials and methods

A retrospective case review was performed including all cases of skin metastases from primary internal malignancies diagnosed at the Department of Pathology at the Maastricht University Medical Centre+ from 2007 to 2021. The clinicopathological data were collected and immunohistochemical and molecular diagnostic tests were performed to confirm the primary origin of the metastases.

Results

We identified 152 cases (71 female; 31 male patients) of cutaneous metastases of internal malignancies. 28 patients (20 women and 8 men) were diagnosed with multiple cutaneous metastases. Among the female patients, the most common primary tumour was breast cancer (50% of the cases), followed by lung (13.6%), gynaecological (7.3%), and gastrointestinal origin (7.3%). Among the male patients, the most common primary sites were gastrointestinal and lung origin (altogether, 50% of the cases). In 19 patients, the cutaneous metastasis was the first presentation of a clinically silent internal malignancy (18.6%), of which most (78.9%) represented metastatic lung carcinomas. Finally, metastasizing patterns were different across tumour types and gender.

Conclusion

Breast, lung, gastrointestinal, and gynaecologic cancers are the most common primary tumours demonstrating skin metastases. Infrequently, cutaneous metastases can be the first clinically visual manifestation of an underlying not yet diagnosed internal malignancy; therefore, occasional broad immunohistochemical profiling, molecular clonal analysis, and a continuous high level of awareness are necessary for a precise diagnosis of cutaneous metastases of internal malignancies.