The phrase "a distinct case" is correct and usable in written English.
It can be used to refer to a specific situation or instance that is clearly different from others.
Example: "This is a distinct case that requires special attention due to its unique circumstances."
Alternatives: "a separate instance" or "a unique situation".
Note that my fifteen-year-old is a distinct case but not a special one.
Indeed, this year the film-maker is feeling a distinct case of deja vu.
The multilingual signs in the station added to the impression that Brixen suffered from a distinct case of indecisiveness.
Politically motivated hackers began to emerge in the late 1990s — each one with a distinct case and a focused target.
Between the Mycenaean period and the 8th century the instrumental ceased to exist as a distinct case, its role having been taken over by the dative.
The tech companies are also a distinct case because they have been variously cast as collaborators in mass data collection, dupes, willfully blind instruments, dishonest brokers, purveyors of compromised products, targets, innocent victims — everything but clever.
Not until the 1840s did American judges (relying partly on earlier English cases) recognize a distinct cause of action for "trademark" infringement.
We report the epidemiologic and clinical characteristics of a geographically distinct case series of live and deceased suspected EVD patients, from whom samples were collected and tested by the CMLTT.
And it's the case that if one doesn't look back to history, one tends to see each case -- Kosovo, the debate over NAFTA, relations with China -- as a distinct, discreet case study with no overarching view of what it says about our past or how it relates to our past and what it might say about our future.
The results on samples collected from 47 different patients (the sequences from each patient formed a distinct test case) with a median of 32 sequences (range 10 57) and 357 sites (range 330 473), representing env and pol sequences from subtype B and subtype C viruses are shown in Tables 2 and 3.
In this case, it is an important distinction that our patient did not have "Lymphangitis" associated with her "Cellulitis, left foot," as opposed to a distinct separate case where the diagnosis of "Lymphangitis was present".
