According to gastroenterologist William Haubrich: A patient may exhibit sudden, intense, epigastric pain and a rigid abdomen.
Such a patient is said to have a forme fruste of acute free perforation as a complication of his peptic ulcer disease.
First, as an antiquarian’s term it refers to a coin, medal or ancient stone on which figures and characters can no longer be recognized due to wear.
It was in this sense of "indistinctness due to wear or through long use" that the French internist Armand Trousseau (1801–67) first employed the term in connection with an obscured form of Graves' disease, which he described as a "…maladie dite fruste par l’absence du goitre et de l’exophthalmie" ("…disease said to be crude [i.e., indistinct] for its absence of goiter and exophthalmia")[2] The sense of the term in medicine has slightly evolved to mean a "not fully developed form of an illness", rather than simply an obscure form.
Sigmund Freud (1856–1939) often used the term forme fruste in connection with incomplete or obscured cases of neuroses and psychoses and thus the literature of psychoanalysis is replete with it.