Introduction:
Fallopian tube carcinoma is a rare neoplasm derived from mucous tissue located inside fallopian tubes. The disease is most prevalent in women in 4th to 6th decade. The early stages are asymptomatic, advanced stages can be diagnosed based on Latzko's triad: serous, amber-colored discharges, pathological resistance during abdominal physical examination, colic abdominal pain alleviating when the discharge is released.

Aim:
To present a case of an uncommon neoplasm found by mistake.

Case study:
We present a case of a 60-year-old asymptomatic woman admitted to gynecological–oncological department with a suspicion of a neoplasm in the left ovarian cyst. The surgery performed excluded the possibility of malignancy of the ovary, but the histopathological examination afterwards revealed the presence of a high-grade serous carcinoma in the right fallopian tube. In CT imaging enlarged, paraaortic lymph nodes were revealed. The patient underwent a surgery and received postoperative adjuvant chemotherapy.

Results and discussion:
The fallopian tube cancer may be related to ovarian cancer. It can be found on one side or bilaterally. There is a need for further diagnostic proceedings in order to confirm diagnosis and to select optimal treatment. Main negative prognostic factors are stage and the lack of optimal cytoreduction. Depending on the staging appropriate treatment is chosen with surgery being the basic procedure. Adjuvant chemotherapy is used. Radiotherapy is only justified as a palliative procedure.

Conclusions:
The fallopian tube carcinoma if often found either during or after the surgery. The optimal treatment is the excision of the reproductive organs with lymphadenectomy.