The phrase "a different case of" is correct and usable in written English.
It can be used to indicate that a situation or example is distinct from another, often in a comparative context.
Example: "While this incident is serious, it is a different case of negligence compared to the previous one."
Alternatives: "a separate instance of" or "another example of".
Goldberg (1995) presented a different case of relatively lexicalized construction in English, the "way" construction.
Each subset represents a different case of the atom-wise similarity calculation using different information and parameters.
The first season of Veronica Mars features a different "case of the week" each episode, and the season-long mystery of Lilly Kane's murder.
And, in a different case of a life-threatening and rare food allergy, 14-year-old Lauren Robinson from Colorado has a dairy allergy so severe that being near anyone who has recently consumed it could kill her.
Continuing, she said, "Two months before his pre-trial custody ended, Sakkas was accused again of a different case of terrorism, so his detention was extended for another six months.
The episodes of the series have a distinct structure: Veronica investigates a different "case of the week" while continually trying to solve a larger mystery which spans several episodes or a whole season.
However, it is a different case for many of the other research groups involved.
Cuba is a different case because of domestic political concerns, notably Florida's large Cuban-American electorate.
Take a different case, that of the mythical sword Excalibur extracted from a rock by King Arthur.
He had roles for everybody, although Bradley was a different case — given his huge mix of talent and unselfishness.
Fayyad, an ally of the prime minister and one who would clearly like to have his job someday, presents a different case study in the use of power.
