Further, as mesenchyme migrate from more than one area, failure in migration and in the fusion of mesoderm results in formation of two genital tubercles  and double penises, as well as producing associated anomalies such as double bladders, double urethra, double colons and imperforated anus. Failure in proper fusion of urethral folds results in hypospadias. Failure in mesoderm cell migration results in epispadia.Diphallia is a rare abnormal external genitalia. The cause is uncertain, but most scientists agree that diphallia is a defect of genital tubercle, and occurs at about week three of gestation, when caudal cell mass of mesoderm is affected by various external environmental factors including drugs, infections and malfunctioning homeobox genes. Treatment
Treatment is a case-by-case analysis taking into account considerations for medical and ethical reasons, and involves surgical excision of the non-functioning penis. See also
Bifid penis
Supernumerary body part
Polyorchidism
Penile agenesis
Uterus didelphys
Vaginal septum

References
Notes
A scientific paper of triphallia (three penises) in a marine snail was reported. (Castillo, Viviana M; Brown, Donald I (2012). "One Case of Triphallia in the Marine Snail Echinolittorina peruviana (Caenogastropoda: Littorinidae)". International Journal of Morphology. 30 (3): 791–796. doi:10.4067/S0717-95022012000300003.) In 2021, the first known case of a human with triphallia was recorded in Iraq. ("Triphallia: First Human Case of Baby Born With Three Male Genitalia Reported". 3 April 2021.) Further reading
Chadha R, Bagga D, Gupta S, Mahajan JK. (July 2001). "Complete diphallia associated with features of covered exstrophy." 36 (7): E12, W.B. Saunders Company. National Center for Biotechnology Information, US National Library of Medicine, National Institutes of Health


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Meningioma, also known as meningeal tumor, is typically a slow-growing tumor that forms from the meninges, the membranous layers surrounding the brain and spinal cord. Symptoms depend on the location and occur as a result of the tumor pressing on nearby tissue. Many cases never produce symptoms. Occasionally seizures, dementia, trouble talking, vision problems, one sided weakness, or loss of bladder control may occur.Risk factors include exposure to ionizing radiation such as during radiation therapy, a family history of the condition, and neurofibromatosis type 2. As of 2014 they do not appear to be related to cell phone use. They appear to be able to form from a number of different types of cells including arachnoid cells. Diagnosis is typically by medical imaging.If there are no symptoms, periodic observation may be all that is required. Most cases that result in symptoms can be cured by surgery. Following complete removal fewer than 20% recur. If surgery is not possible or all the tumor cannot be removed radiosurgery may be helpful. Chemotherapy has not been found to be useful. A small percentage grow rapidly and are associated with worse outcomes.About one per thousand people in the United States are currently affected. Onset is usually in adults. In this group they represent about 30% of brain tumors. Women are affected about twice as often as men. Meningiomata were reported as early as 1614 by Felix Plater. Signs and symptoms
Small tumors (e.g., < 2.0 cm) usually are incidental findings at autopsy without having caused symptoms.