My male patient aged about 80 years, c/o pain left breast for last 4 months,pain is relieved after hot fomentation.There is no constitutional symptom.Patient is hypertensive and diabetic.On examination there is tender left nipple,no lymph node palpable in axilla.He has taken antibiotics & antiinflammatory without any response.Ultrasound report revealed hypoecoic lesion 10 mm/4mm in subareolar tissue,margins irregular. What is the differential diagnosis?

How to approach the case?