Recurrence that poses the biggest problem after breast-conserving surgery is local recurrence. Particularly, in the case of inflammatory breast recurrence which is rare but has a specific pathologic nature, it is important to elucidate the pathology and risk factors and to consider appropriate countermeasures. In the present study, we classified 133 cases of recurrence following breast-conserving surgery, collected from 18 key hospitals/institutes in Japan. Recurrence types were divided into three groups, namely, inflammatory breast recurrence, noninflammatory breast recurrence and distant metastasis only, and the risk factors involved in recurrence were investigated by the case control study allotting 2 controls to each case. The study population consisted of 9 cases of the inflammatory type, 64 cases of the noninflammatory type and 60 cases of distant metastasis. The significant risk factor for inflammatory breast recurrence was positive lymph node metastasis, which was significantly more frequent in lymphatic invasion-positive cases unlike in the distant metastasis group. The positive surgical margin and nonradiation therapy which have been shown to be significant risk factors for noninflammatory breast recurrence were entirely unrelated with inflammatory breast recurrence. In addition, the inflammatory-type recurrence time was as short as about 12 months irrespective of whether radiation therapy was performed or not. The inflammatory type was accompanied with local wide extension (cancerous embolus of the dermal lymphatic vessels), and distant metastasis (lymphangitis carcinomatosa) at the time of recurrence, and further surgery was impossible in most cases, with a significantly poorer prognosis than the other recurrence types. These findings suggest that this recurrence corresponds to the so-called 'occult' case of primary inflammatory breast carcinoma. We think it important to predict this recurrence by close pathological examination, particularly in patients with lymph node metastasis, and to consider appropriate measures.