Reinke crystals are rod-like

cytoplasmic inclusions In cellular biology, inclusions are diverse intracellularShively, J. M. (ed.). (2006). ''Microbiology Monographs Vol. 1: Inclusions in Prokaryotes''. Berlin, Heidelberg: Springer-Verlaglink non-living substances (ergastic substances) that are not ...

which can be found in

Leydig cell Leydig cells, also known as interstitial cells of the testes and interstitial cells of Leydig, are found adjacent to the seminiferous tubules in the testicle and produce testosterone in the presence of luteinizing hormone (LH). They are polyhedra ...

s of the

testes A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoste ...

. Occurring only in adult humans and wild bush rats, their function is unknown. Ovarian stromal tumors having a predominant pattern of fibroma or thecoma but also containing cells typical of steroid hormone-secreting cells were reported. Some of the tumors were classified as luteinized thecomas because the steroid cells resembled lutein cells and lacked crystalloids of Reinke. But others were classified as stromal Leydig cell tumors as seen in tumors of the testes because Reinke crystalloids were identified in the steroid cells. The Stromal Leydig tumors occurred at an average age of 61 years and were associated with Ovarian hyperandrogenism which led to virilization in some cases, endometrial hyperplasia in other cases, and endometrial hyperplasia with carcinoma in the rest of the cases. Luteinized thecomas and stromal Leydig cell tumors are indistinguishable except for the presence of crystalloids of Reinke in the latter. In view of the prolonged search that is necessary to find these structures in some stromal Leydig cell tumors and their well-known absence in the majority of testicular Leydig cell tumors, it is reasonable to assume that an unknown proportion of tumors in the luteinized thecoma category are unrecognized stromal Leydig cell tumor

Another ovarian tumor where Reinke crystalloids were noted is the Brenner tumour, an epithelial-stromal ovarian tumor distinguishable by nests of transitional epithelial cells (urothelial) with longitudinal nuclear grooves (coffee bean nuclei) in abundant fibrous stroma

Also recall that the "coffee bean nuclei" are the nuclear grooves exceptionally pathognomonic to the sex cord stromal tumor, the ovarian granulosa cell tumor, with the fluid-filled spaces Call-Exner bodies between the granulosa cell

They are large enough to be seen in an

optical microscope The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. Optical microscopes are the oldest design of micro ...

and can be visualized using Giemsa,

trichrome Trichrome staining is a histological staining method that uses two or more acid dyes in conjunction with a polyacid. Staining differentiates tissues by tinting them in contrasting colours. It increases the contrast of microscopic features in ...

Gram The gram (originally gramme; SI unit symbol g) is a unit of mass in the International System of Units (SI) equal to one one thousandth of a kilogram. Originally defined as of 1795 as "the absolute weight of a volume of pure water equal to th ...

, and PAS stains. Reinke crystals are rare in normal testes, but are found in approximately 1/3 of all

Leydig cell tumour Leydig cell tumour, also Leydig cell tumor (US spelling), (testicular) interstitial cell tumour and (testicular) interstitial cell tumor (US spelling), is a member of the sex cord-stromal tumour group of ovarian and testicular cancers. It arises ...

s. These crystals are named after the German anatomist Friedrich Berthold Reinke.

References

{{reflist, 1 Cell anatomy Male genital neoplasia