Synchronous Occurrence of Primary Breast Carcinoma and Primary Colon Adenocarcinoma

A 65-year-old female patient presented to the emergency clinic with abdominal pain, meteorism, and intermittent rectal bleeding. Colonoscopy was performed, and a hepatic flexure tumor was detected. Histopathological examination of biopsy revealed adenocarcinoma. Thoracoabdominal CT was performed for staging, and a spiculated contour mass was found incidentally on the left breast. Mammography and ultrasonography were performed for the cause of these findings, and suspicious lesions of malignancy were seen in the left breast. Invasive ductal carcinoma was detected in core needle biopsy samples from lesions. In the multidisciplinary council consisting of oncologist, pathologist, radiologist, and general surgery specialist, it was decided to perform breast operation first and then colon operation, followed by adjuvant chemotherapy. In the first operation, left total mastectomy and sentinel lymph node biopsy were performed. One week after her initial operation, the patient underwent right hemicolectomy. After operations, the patient did not develop postoperative complications and was sent to medical oncology department for adjuvant chemotherapy.


Background
Synchronous primary malignant tumors are di cult to diagnose and plan for treatment. It is possible to skip asymptomatic synchronous tumors at the time of diagnosis. Because of the lack of de nitive guidelines for synchronous tumors, evaluation of the clinical ndings of the patient and establishment of the patient-speci c treatment strategy are necessary. ese can be achieved with a multidisciplinary approach. We present a case in which synchronous breast tumor was detected incidentally on a computed tomography for staging of a colon tumor.

Case Presentation
A 65-year-old female patient presented with complaints of right upper quadrant pain, meteorism, and intermittent rectal bleeding. She stated that her pain and dyspeptic complaints were lasting for 2 months, and for the last 15 days, she had rectal bleeding in small amounts twice. Physical examination showed pain and tenderness with palpation in the lower and upper right quadrants. ere was no pathology at the digital rectal examination. ere was no characteristic in the history and family history of the patient.
e occult blood test in the stool was positive. An ulcerative mass in the hepatic exure region without obstruction was seen on colonoscopy. Histopathologic examination of the biopsies revealed adenocarcinoma. oracoabdominal tomographic examination for the staging of colon cancer revealed multiple thickening of the colonic wall consistent with malignancy, especially in the hepatic exure level and multiple mesenteric lymphadenomegalies. In addition, a spicule-shaped lesion with massive mass, 2 cm in diameter, was found in the outer quadrant of the left breast ( Figure 1). On a whole-body PET-CT examination, a lesion with increased FDG uptake accompanied by an increase in irregular wall thickness at hepatic exure level was seen ( Figure 2). e patient's breast was reexamined, and a palpable mass was not detected. On mammogram, a 15 mm diameter hyperdense lesion was observed in the upper external quadrant of the left breast with a spiculated contour. A second focal spot was seen with the same features and 18 mm in diameter near this lesion. Both lesions were con rmed by breast ultrasonography. Invasive ductal carcinoma was detected in ultrasound-guided core needle biopsy of these lesions. So, bifocal breast cancer was detected. Immunohistochemical examination revealed positive estrogen and progesterone receptors. Cerb B2 was negative, and Ki-67 ratio was 5%. We also performed a cytokeratin 7, cytokeratin 20, ER, PR, and HercepTest immunohistochemistry on one colon adenocarcinoma para n block to ensure that the colon adenocarcinoma represents a primary malignancy and not metastasis from breast carcinoma. e test result was negative.

Treatment
In the multidisciplinary oncology council, it was decided to perform breast surgery rst. e patient underwent simple mastectomy and sentinel lymph node biopsy. Since no invasion was seen in SLNB in frozen examination, axillary dissection was not performed. ere were no complications in the early postoperative period. On the sixth postoperative day, right hemicolectomy and ileotransversostomy were performed. Histopathological examination of the surgical specimens revealed 12 mm and 15 mm diameter invasive ductal carcinoma in two separate foci of the mammary gland.
ere was no metastasis in SLNB, and the pathological stage was T1N0. Examination of the colon segment revealed an invasive adenocarcinoma of 7 × 6 × 2 cm in size, with invasion to the level of muscularis propria. ere were 28 lymph nodes in the mesentery of the resected colonic segment. No metastasis was detected. e pathological stage was identi ed as T2N0Mx.

Outcome and Follow-Up
After both surgeries, the patient did not develop postoperative complications and was sent to the medical oncology department for adjuvant chemotherapy.

Discussion
Cancers developing from multiple origins are called multiple primary cancers (MPCs) and are rarely seen. e average frequency is reported between 0.73% and 11% [1]. If two di erent tumors originating in the same patient are detected at the same time or within 6 months, this is a synchronous tumor. If the second tumor is detected 6 months later, it is called a metachronous tumor [2]. We detected a synchronous breast cancer incidentally in a tomographic examination for staging in our case with primary colon cancer. e most common malignancy in women is breast cancer. e second one is colon cancer. Fischer et al. reported that the incidence of breast and colon cancer in women at the same time is 3.85% [3]. Various imaging modalities (such as CT, MR, and PET-CT) are used in the staging and monitoring of malignancies. It should always be kept in mind that synchronous tumors may be encountered during their evaluation. As a matter of fact, Karayiannakis et al. [4] had randomly seen synchronous breast cancer in the chest CT scan. Karaduman et al. [5] have detected synchronous colon cancer in patients who have had PET-CT examinations to investigate breast cancer. e clinical and pathological features of synchronous tumors are not fully established. Kimura et al. reported a correlation between familial history and synchronous tumors [6]. Our patient does not ful ll the criteria of cancer family syndrome; therefore, no genetic testing was done to her [7]. ere is no de nitive guideline for the treatment of synchronous tumors. Because of this, the treatment plan of the patient is specially determined for each patient as the outcome of the multidisciplinary discussions. In our multidisciplinary council consisting of oncologist, pathologist, radiologist, and general surgery specialist, it was decided to perform the operation of breast cancer rst and then colon carcinoma, followed by adjuvant chemotherapy. In this decision, no colonic obstruction and bleeding in the patient suggested that emergent surgery was not required for colon carcinoma. e lesser mortality of breast surgery a ects our decision also. In fact, the rst surgery that is thought to have less morbidity makes it possible to perform the second operation in a short period of time, since it does not disturb the general condition of the patient [8]. In patients with synchronous tumors, the prognosis depends on each tumor stage independently.

Learning Points/Take Home Messages
(1) It should be remembered that in patients with malignancy, a second tumor of a di erent origin should be considered in systemic physical examination and in all laboratory tests and imaging performed. (2) ere is no de nitive guideline for the treatment of synchronous tumors. e treatment plan should be planned speci cally for each patient with a multidisciplinary approach.

Conflicts of Interest
e authors declare that they have no con icts of interest.