The phrase "infrequently seen" is correct and usable in written English.
You can use it to describe something that is seen or occurs only occasionally. For example, "The rare Black Goat of Caerbannog is an infrequently seen creature."
Severe adolescent idiopathic scoliosis with respiratory insufficiency is infrequently seen in North America currently.
The first lineage, GN1, was largely restricted to Guinea and was infrequently seen in Sierra Leone.
WE think of Emilio as we do old friends infrequently seen.
Once common on both slopes of Mexico, Wild Turkeys are infrequently seen there victims of hunting and habitat loss.
The evening opened with the all-female first movement of Balanchine's exquisite, and infrequently seen, "Symphonie Concertante".
"Abstraction of Stream" an infrequently seen pastel-on-paper work from 1921, is one of the artist's most distinctive abstracts.
Mr. Preljocaj is the best known of the bunch, but even his work is infrequently seen in New York.
The type most commonly encountered in children worldwide though infrequently seen in developed countries is acute post-streptococcal nephritis.
Even on its breeding grounds, the Ash-colored Cuckoo is an elusive and very infrequently seen bird; it inhabits a variety of wooded habitats in the lowlands.
A robust emergency simulation educational program incorporates simulation-based scenarios for infrequently seen medical entities, resuscitation procedures, communication, team training and leadership into the clinical curriculum.
The geographically most widespread species of Nonnula, the Rusty-breasted Nunlet is, nonetheless, a rather infrequently seen bird over most of its range, in common with its congenerics.
