Signet ring cell carcinoma of the rectum: atypical metastatic presentation

Signet cell rectal carcinoma with prostatic involvement detected by FAPI-04 PET-MRI fusion

A 60-year-old male patient diagnosed with mucinous adenocarcinoma of lower third of rectum underwent abdominoperineal resection and permanent colostomy followed by adjuvant chemotherapy. Response evaluation with F-18 FDG PET-CT showed a complete metabolic response. After 6 months, CEA levels started increasing and clinically a recurrence was suspected. A restaging FDG PET-CT showed no obvious malignant disease. Patient presented again within a month with complaints of urinary retention and haematuria. CEA levels were further elevated, and Ga-68 FAPI-04 (FAPI) PET-CT was performed. FAPI PET-CT revealed prostatic and seminal vesicle disease involvement. Additionally, an MRI of pelvis was done and fused with FAPI PET for confirmation of prostatic involvement.

Nonbacterial Thrombotic Endocarditis With Leptomeningeal Carcinomatosis: A Rare Presentation of Advanced Rectal Adenocarcinoma

Nonbacterial thrombotic endocarditis (NBTE) is a rare condition characterized by the formation of sterile vegetations on valvular structures. Commonly asymptomatic in early stages resulting in systemic emboli as its initial manifestation. NBTE is found to be associated with diseases, which induce hypercoagulability, and, most commonly, is associated with malignancy. Rectal signet ring cell adenocarcinoma is an uncommon histological type of rectal cancer with a poor prognosis and aggressive nature. We present a rare manifestation of advanced rectal signet cell adenocarcinoma discovered due to manifestations of NBTE and leptomeningeal carcinomatosis.

Signet ring cell carcinoma of rectum metastasizing to synchronous renal cell carcinoma: a case report

BACKGROUND

Rectal signet ring cell carcinoma is a rare type of colorectal adenocarcinoma characterized by an aggressive biological behavior and poor prognosis. The co-occurrence of colorectal carcinoma and renal cell carcinoma (RCC) has found in many hundreds of patients, many of whom also have additional malignancies. Cancer to cancer metastasis is rare and an uncommon phenomenon in malignancy, especially at the time of initial diagnosis, suggesting a genetic susceptibility.

CASE PRESENTATION

We present the case of a 66-year-old Macedonian man with synchronous rectal signet ring cell carcinoma and RCC with tumor to tumor metastasis feature. He underwent a left nephrectomy and anterior rectal resection after complaining of constipation for 3-4 months and the appearance of synchronous tumors on the imaging studies. Morphology and immunohistochemical analysis of specimens from the RCC revealed signet ring cells identical to the rectal signet ring cell carcinoma. The next-generation sequencing study revealed mutations in TP53 and ERBB2, and microsatellite stable signet ring cell carcinoma was determined by deoxyribonucleic acid (DNA) sequencing.

CONCLUSIONS

Cancer to cancer metastasis, although rare, needs to be considered in synchronous tumors. RCC, when diagnosed in multiple synchronous tumors, should be examined carefully. The paucity of reported cases indicates the need for advanced research in imaging methods for metastasis and new therapeutic approaches.

Rare Signet Ring Cell Adenocarcinoma of the Colon Metastasis to the Orbit

Metastases arising from primary tumors of the gastrointestinal tract are not commonly encountered in the orbit. Colorectal carcinomas are subcategorized based on morphological and genetic characteristics with these distinctions bearing therapeutic and prognostic significance. The behavior of these subcategories, including their propensity for orbital metastasis, differs, and clinicians treating these tumors must be aware of their metastatic profiles. This report describes a 51-year-old female with right upper lid swelling and ptosis ultimately found, what we believe to be, the first reported case of signet ring cell colon carcinoma metastasizing to the levator muscle and superior orbit. This case serves as a reminder to all clinicians to consider orbital metastasis even in malignancies not typically found in this location.