### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
i have a painless swollen lymph node on my left neck.  I think it is in the posterior cervical area.  I am not sick and am under curam antibiotics now given by doctor.  It has been one week and the swell seems the same.  Any cause for concern?  is it most definitely cancer since it is in the posterior cervical area?

### output:

Hi this is Chat Doctor. Thanks for the opportunity to help you. Presence of one painless lymph node in the posterior triangle of neck doesn't have to be cancer always and that to as per your description it has only lasted for one week. Some additional information will be beneficial like your age, sex, smoker or alcoholic and bit of elaboration of your symptoms like history of sore throat, fever, weight loss, evening rise of temperature. Weight loss (T. B, Malignancy)should be significant more than 10 kg in 6 months, any scalp infection like seborrhea dermatitis and lastly malignancy:- Hodgkin's lymphoma, NHL,secondaries due to known, unknown or occult primary including visceral malignancies. However chances of malignancy should be considered only at the last. Most common possible diagnosis are:- sore throat’T. B lymphadenitis, kikuchi fugimotos disease(rare), seberrhoeic dermatitis, Malignancy.an FNAC should be tried first and if it confirms T. B then start ATT for 6 months. If FNAC is inconclusive do an excision biopsy. If rarest of the rarest circumstances it turns out to be malignant then Triple or Pan endoscopy to find the primary followed by definitive treatment of primary with MRND but in your case it will be the rarest possibility. Kindly get Total count, E.S.R, Mantoux test to rule out T. B and chest x-ray p/a view. This will be very helpful to come to diagnosis. Kindly let me know if the consultation was beneficial. Regards