One of the following disease will show urinary bladder calcification radiologically which resembles fetal head in pelvis:

A plain film of the abdomen may show areas of grayness in the flank (enlarged hydronephrotic kidney) or in the bladder area (large tumor). Opacifications (stones) may be noted in the kidney, ureter, or bladder. Linear calcification may be seen in the ureteral and bladder walls. Punctate calcification of the ureter (ureteritis calcinosa) and a honeycombed calcification of the seminal vesicle may be obvious. The classic presentation of a calcified bladder, which looks like a fetal head in the pelvis, is pathognomonic of chronic urinary schistosomiasis. Ref: Tanagho E.A., Kane C.J. (2008). Chapter 14. Specific Infections of the Genitourinary Tract. In E.A. Tanagho, J.W. McAninch (Eds), Smith's General Urology, 17e.