An adenomatoid tumor is a benign, non-cancerous growth that can occur in various parts of the body. These tumors are not harmful and do not spread. They are often identified incidentally during medical examinations.
Understanding Adenomatoid Tumors
Adenomatoid tumors are rare and benign, meaning they do not spread. They originate from mesothelial cells, which line various body cavities and organs like the pleura, peritoneum, and pericardium. The exact cause is not fully understood, but some research suggests a link to somatic missense mutations in the TRAF7 gene, which can lead to abnormal activation of the NF-kB pathway.
Under a microscope, adenomatoid tumors can exhibit various patterns, including solid, cystic, or mixed arrangements of cells. They are typically composed of cords and tubules of cuboidal to columnar cells, which often have a vacuolated cytoplasm, interspersed within a fibrous stroma. These tumors are slow-growing and often remain asymptomatic. Most measure around 2.0 cm, although they can range up to 5.0 cm.
Where Adenomatoid Tumors Are Found
Adenomatoid tumors show a strong predilection for the genital tract in both males and females. In males, they are most commonly found in the epididymis, a coiled tube at the back of the testicle that stores and carries sperm. They are the most common benign tumor of the testicular adnexa and the most frequent extratesticular neoplasm after lipoma, accounting for approximately 30% of paratesticular masses. Less commonly, they can also arise in the spermatic cord, tunica vaginalis, or, rarely, within the testicle.
In females, adenomatoid tumors are most frequently identified in the uterus, particularly the myometrium, and the fallopian tubes. They are considered the most common benign mesothelial neoplasm of the fallopian tube. These tumors have also been reported in other locations, including the adrenal gland, liver, pancreas, mesocolon, and pleura.
How Adenomatoid Tumors Are Identified
Adenomatoid tumors are frequently discovered incidentally during imaging studies. For instance, they may be found during an ultrasound or MRI of the pelvic or scrotal region. While often asymptomatic, they can sometimes present as a slow-growing, painless mass, particularly in the scrotum. Depending on their size or location, they might cause mild pain or swelling.
Imaging modalities like ultrasound are often the first step in evaluation, showing a well-defined, solid, and circumscribed nodule. Magnetic Resonance Imaging (MRI) can provide additional detail and help determine if the mass is within or outside an organ. However, distinguishing an adenomatoid tumor from other types of masses, including malignant ones, can be challenging based solely on imaging. A definitive diagnosis requires a pathological examination of tissue obtained through a biopsy or after surgical removal. Microscopic analysis confirms the benign nature and characteristic cellular patterns of an adenomatoid tumor.
Treatment and Outlook
Given their benign nature, active treatment may not always be necessary, especially if they are small and asymptomatic. In such cases, a “watchful waiting” approach, involving regular monitoring, might be recommended. If the tumor causes symptoms, grows large, or if there is uncertainty about the diagnosis, surgical removal is performed.
Surgical excision is considered both diagnostic and therapeutic, often leading to a complete resolution. When located in the male reproductive tract, surgeons preserve testicular function and fertility during removal. The prognosis for individuals with adenomatoid tumors is excellent due to their non-malignant behavior. Recurrence after complete surgical removal is rare, and there are no reports of these tumors spreading.