This paper describes a student-centered case study program concerning the tumor pathology course for first year students in medical school under the traditional curricular structure. A traditional, discipline-oriented, lecture-laboratory approach was partly modified by introducing a tutuorial session using a modified case matrix format during the laboratory hours without altering the general scheme of the existing system. Small group tutorial sessions were set with the development of learning objectives emphasizing clinicopathologic reasoning and early exposure to future practical presentation which was followed by the large class session; each tutorial was supplied with a short clinical history, gross kodachrome slides, and microslides. The session for problem identification was replaced by proving a series of instructor-designed questions for both pathology and interdisciplinary correlation during which pedagogical implication was stressed the most. Student's active participation, development of self learning skill and vigorous teaching-learning process among students, and motivation/relevance for forthcoming pathology study were among the benefits conferred by this modification. We conclude that this approach is an interim step to meet the advantages of problem-based learning even in a traditional curricular structure.