What is Ranne complex?: (A) Necrotic material undergoing calciﬁcation, (B) The stage is seen in the formation of granuloma, (C) Central necrosis surrounded by lymphocytes, (D) All of the above
Answer is A. The central part of the TB lesion contains caseous, soft, and cheesy necrotic material (caseous necrosis). This necrotic material may undergo calcification at a later stage called Ranne complex, in the lung parenchyma and hilar lymph nodes in few cases.
Key concept:
Necrotic material undergoing calciﬁcation which is seen in TB is known as Ranne complex.
Ref: Shafer's textbook of oral pathology 7th edition page 320