"Collision" metastasis from unknown primary squamous cell carcinoma and papillary microcarcinoma of thyroid presenting as lateral cervical cystic mass

[Metastatic lymph node collision of a prostatic adenocarcinoma and an urothelial carcinoma and review of the literature]

INTRODUCTION

Tumor collision is the encounter of two tumors from two different topographical sites. Cases of metastatic lymph node collision are exceptional. We report the case of a metastatic lymph node collision of an urothelial carcinoma and a prostatic adenocarcinoma.

OBSERVATION

A 61-year-old man was hospitalized for a right nephroureterectomy with peri-ureteral lymph node dissection. He was followed since 2004 for prostatic adenocarcinoma and treated with radical prostatectomy then radiation therapy 4 years later due to a new increase of PSA. In the follow-up, an urothelial carcinoma of the lower right ureter was discovered in 2014. Histological analysis of a peri-ureteral lymph node showed a double metastasis of urothelial and prostatic origin. The prostatic adenocarcinoma was composed of acinar and ductal subtypes. Immunohistochemical study including CK7, CK20, PSA, GATA3, P63 antibodies confirmed the distinct phenotype of the 2 tumors.

DISCUSSION

Metastatic collision of urothelial carcinoma and prostatic adenocarcinoma has been reported in 4 cases only. Our review of literature shows that prostatic adenocarcinoma always precedes the urothelial carcinoma. Immunohistochemical study, when carried out for distinguishing both tumors, should include CK7, CK20 and PSA. GATA3, androgen receptor and P63 could be added in a second time.

Three Metachronous Cases of HER2-Positive Breast Cancer Accompanied with Thyroid Cancer

BACKGROUND

Breast carcinoma (BC) and papillary thyroid carcinoma (PTC) occur predominantly in women. Many studies have shown that PTC is common among women with BC. Collision metastases in lymph nodes do occur but are not common.

CASE REPORT

Here we report 3 metachronous cases of BC with PTC. PTC developed after BC in each case. Histology and immunohistochemistry revealed that HER2 status was positive in each BC, and in 1, concurrent metastases of BC and PTC were shown in a lymph node of the left cervical region.

CONCLUSION

From our results, we speculate that women with HER2-positive breast cancer may be at a higher risk for thyroid cancer than other cancers. Finding 2 distinct types of cancer metastasized to 1 lymph node in a patient may, therefore, warrant a high index of suspicion and the use of immunohistochemical stains to differentiate the types of collision tumors.