LE 4 BREAST/PELVIS (MALE/FEMALE) Flashcards
- The most common histologic type of cervical carcinoma is:
A. Adenocarcinoma
B. Mucinous carcinoma
C. Serous carcinoma
D. Squamous carcinoma
D. Squamous carcinoma
Rationale: Squamous cell carcinoma accounts for approximately 70-80% of cervical cancers and arises from the transformation zone of the cervix. It is associated with persistent infection by high-risk human papillomavirus (HPV) types, especially HPV 16 and 18.
- What is the recommended examination in younger patients who present with breast masses?
A. CT
B. Mammography
C. MRI
D. Ultrasound
D. Ultrasound
Rationale: In younger patients, breast tissue is denser, making mammography less effective. Ultrasound is preferred as the initial imaging modality because it better differentiates between solid and cystic masses and does not involve radiation.
Ultrasound : Under 20 y.o
- The main purpose of screening mammography is:
A. Assess for abnormalities in indeterminate mammograms
B. Evaluate breast abnormalities in symptomatic patients
C. For special mammographic views, breast ultrasound, or MRI
D. Screen asymptomatic women for early breast cancer
D. Screen asymptomatic women for early breast cancer
Rationale: The main purpose of screening mammography is early detection of breast cancer in asymptomatic women, allowing for earlier treatment and better prognosis. This reduces mortality rates.
- On screening mammography, breast cancer survival is largely influenced by:
A. Size of tumor
B. Pleomorphic calcifications
C. Spiculated margin
D. Architectural distortion
A. Size of tumor
Rationale: Tumor size is a significant prognostic factor for survival in breast cancer. Smaller tumors detected on screening mammography are more likely to be treated successfully and have a better outcome.
- The spread of cervical cancer is primarily by:
A. Direct extension
B. Hematogenous spread
C. Lymphatic metastasis
D. Peritoneal seeding
A. Direct extension
Rationale: Cervical cancer primarily spreads by direct invasion to adjacent structures, such as the vagina, parametrium, and bladder. Lymphatic spread and hematogenous metastasis occur in advanced stages.
- The most common gynecologic malignancy is:
A. Cervical cancer
B. Endometrial cancer
C. Ovarian cancer
D. Uterine sarcomas
A. Cervical cancer
- The most common germ cell neoplasm of the ovary is:
A. Adenomyosis
B. Cystic Teratoma
C. Leiomyosarcoma
D. Malignant Mixed Mullerian Tumor
B. Cystic Teratoma
Rationale: Mature cystic teratoma (dermoid cyst) is the most common germ cell tumor of the ovary. These benign tumors often contain various tissue types, such as skin, hair, or teeth.
- The most common uterine tumor is:
A. Adenomyosis
B. Endometrioma
C. Leiomyoma
D. Ovarian cancer
C. Leiomyoma
Rationale: Leiomyomas (fibroids) are the most common uterine tumors. These benign smooth muscle tumors occur in up to 70% of women by age 50 and are hormonally responsive.
- In the FIGO endometrial cancer staging, tumor invasion of the cervical mucosa and stroma is:
A. Stage I
B. Stage II
C. Stage III
D. Stage IV
B. Stage II
Rationale: According to FIGO staging, endometrial cancer that invades the cervical stroma is classified as Stage II. This reflects local extension of the tumor beyond the uterine corpus.
- In the FIGO ovarian cancer staging, tumor extension to the uterus and/or fallopian tubes is:
A. Stage I
B. Stage II
C. Stage III
D. Stage IV
B. Stage II
Rationale: In FIGO staging for ovarian cancer, tumor extension to the uterus and/or fallopian tubes is classified as Stage II, indicating pelvic involvement without spread outside the pelvis.
- Leiomyosarcomas usually present clinically as:
A. Rapidly growing pelvic mass
B. Postmenopausal vaginal bleeding
C. Elevated serum CA-125
D. Vaginal prolapse
A. Rapidly growing pelvic mass
Rationale: Leiomyosarcomas are aggressive uterine tumors that often present as rapidly enlarging pelvic masses, especially in postmenopausal women or those with a history of fibroids.
- What is the implication of the Breast Imaging Reporting and Data System (BI-RADS) Category 6 score?
A. Known to be malignant
B. Lesions that have very high probability of being malignant and should undergo biopsy
C. Probability of malignancy is approximately 25% to 35%
D. Spiculated masses and pleomorphic clusters of calcifications
A. Known to be malignant
Rationale: BI-RADS Category 6 indicates a lesion that has already been confirmed as malignant through biopsy, typically awaiting or undergoing treatment planning.
- What is the implication of the Breast Imaging Reporting and Data System (BI-RADS) Category 1 score?
A. Benign finding such as a lipoma, oil cyst, galactocele, intramammary lymph node, etc.
B. Need additional imaging evaluation and/or prior mammograms for comparison
C. No significant findings are present
D. Patient should return for routine screening
C. No significant findings are present
Rationale: BI-RADS Category 1 is assigned when there are no abnormalities or significant findings, and the patient should return for routine screening.
- The primary imaging modality in the evaluation of pelvic malignancies is:
A. Hysterosalpingography
B. MRI
C. Sonohysterography
D. Ultrasound
A. MRI
Rationale: MRI is the preferred imaging modality for evaluating pelvic malignancies due to its superior soft tissue contrast and ability to accurately assess the extent of tumor invasion, especially for staging and treatment planning. It provides detailed information on the anatomy and spread of the malignancy, making it more effective for evaluating pelvic cancers compared to other imaging modalities like ultrasound or CT.
- The key presenting symptom of endometrial carcinoma is:
A. Dyspareunia
B. Elevated serum CA-125
C. Palpable abdominal mass
D. Vaginal bleeding
D. Vaginal bleeding
Rationale: Postmenopausal vaginal bleeding is the most common symptom of endometrial carcinoma, often prompting further diagnostic evaluation.
- Which of the following statements is true regarding the cranio-caudal view on mammography?
A. Compression is applied from superomedial direction
B. Depicts the greatest amount of breast tissue
C. Most useful view in mammography
D. Pectoralis muscle is seen centrally on the film
D. Pectoralis muscle is seen centrally on the film
Rationale:
In a properly performed craniocaudal (CC) view, the pectoralis muscle may be visible centrally in the image, especially when there is good compression and adequate positioning. The presence of the pectoralis muscle centrally is considered a sign of proper positioning. This statement is true.
- CT signs of ovarian cancer include:
A. Age 50-60 years
B. Doppler color flow within the papillary projections
C. Lymph node with fatty hilum
D. Nodularity of the ovarian mass
D. Nodularity of the ovarian mass
Rationale: Nodularity, irregular contours, and solid components on CT are characteristic signs of ovarian cancer, aiding in distinguishing malignant from benign ovarian masses.
- Egg-shell type of calcifications on mammography are usually due to:
A. Arterial calcifications
B. Degenerating fibroadenoma
C. Milk of calcium
D. Oil cysts
D. Oil cysts
Rationale: Egg-shell type calcifications on mammography are characteristic of oil cysts, which are benign findings typically resulting from fat necrosis.
Fat Necrosis: Appears as smooth, round calcifications or eggshell-type calcifications around oil cysts.
- Which of the following types of calcifications seen on mammography are considered benign?
A. Branching
B. “Dot-dash”
C. Large, coarse, and irregular in shape
D. Margins jagged and irregular
C. Large, coarse, and irregular in shape
Rationale: Large, coarse calcifications are typically benign and associated with aging, fibroadenomas, or degenerative changes in the breast.
Degenerating Fibroadenoma: Presents as large, coarse, irregular calcifications.
- One of the hallmarks of endometriosis is:
A. Bright round well-defined structures in the cervix on T2WIs
B. Numerous tiny implants of endometrial tissues on peritoneum
C. Thickening of the junctional zone myometrium on MR
D. Thick-walled fluid-filled adnexal mass
B. Numerous tiny implants of endometrial tissues on peritoneum
Rationale: The presence of small endometrial implants on the peritoneum is a hallmark of endometriosis, leading to pelvic pain and infertility in affected women.
Hallmarks of Endometriosis:
-Numerous tiny implants
-Endometriomas (Chocolate cyst)
-Formation of adhesions (Fibrosis)
- Which of the following statements is a classic mammographic sign of malignancy?
A. Architectural distortion
B. Coarse, irregular calcification
C. Ill-defined margin
D. Spiculated masses
D. Spiculated masses
Rationale: Spiculated masses are a classic mammographic sign of malignancy, characterized by radiating lines or spikes extending from the edges of the mass, suggesting an invasive process.
- Which of the following types of calcifications seen on mammography are considered a primary sign of breast cancer?
A. Branching
B. Clustered pleomorphic calcifications
C. Large coarse and irregular shape
D. Margins jagged and irregular
B. Clustered pleomorphic calcifications
Rationale: Clustered pleomorphic calcifications, varying in shape and size, are considered a primary sign of breast cancer on mammography and warrant further investigation.
- A mass seen on mammography is almost always considered benign when it presents as:
A. Circumscribed well-defined margins
B. Mass following needle aspiration or biopsy
C. Microlobulated margins
D. Round mass
A. Circumscribed well-defined margins
Rationale: Masses with well-circumscribed, smooth, and defined margins are typically benign, such as simple cysts or fibroadenomas.
- Which of the following statements is true regarding ovarian cancer?
A. CA-125 is elevated in the majority of cases
B. Majority are bilateral
C. Majority are germ cell tumors
D. Peak age is premenopausal
A. CA-125 is elevated in the majority of cases
Rationale: CA-125 is elevated in approximately 80% of ovarian epithelial cancers, especially in advanced stages. However, it is not specific to ovarian cancer and can be elevated in other conditions.
- What is the implication of the Breast Imaging Reporting and Data System (BI-RADS) Category 0 score?
A. Benign finding such as a lipoma, oil cyst, galactocele, intramammary lymph node, etc.
B. Need additional imaging evaluation and/or prior mammograms for comparison
C. No significant findings are present
D. Patient should return for routine screening
B. Need additional imaging evaluation and/or prior mammograms for comparison
Rationale: BI-RADS Category 0 indicates an incomplete assessment, requiring additional imaging or previous studies for a conclusive evaluation.
- Which of the following statements is true based on the American College of Radiology Guidelines for screening mammography?
A. Mammography is recommended once a year for women with average risk starting at age 40
B. Women aged 40 and over should undergo screening mammography every 1 to 2 years
C. Women aged 45-49 should have screening every 2 or 3 years
D. Younger patients who present with breast masses should first be evaluated with mammography
A. Mammography is recommended once a year for women with average risk starting at age 40
The American College of Radiology recommends annual mammography starting at age 40 for women with average risk. This aligns with current screening guidelines to help detect breast cancer early when it is most treatable.
- Which of the following statements is true?
A. Majority of women who get breast cancer have histories that place them at higher risk.
B. Not all cancers are seen mammographically.
C. Not all women are at risk for developing breast cancer.
D. Nulliparity or having a first child at an older age is known to decrease the risk for breast cancer.
B. Not all cancers are seen mammographically.
Rationale: Mammography has limitations and may miss some cancers, especially in dense breast tissue. Clinical exams and other imaging modalities may be required for comprehensive evaluation.
- In the evaluation of masses on mammography, the most important characteristic to be assessed is:
A. Density
B. Location
C. Margin
D. Size
C. Margin
Rationale: The margin of a mass is the most critical characteristic in determining malignancy. Ill-defined, irregular, or spiculated margins are highly suggestive of cancer.
- In the FIGO cervical cancer staging, tumor extension to the pelvic side wall is:
A. Stage I
B. Stage II
C. Stage III
D. Stage IV
C. Stage III
Rationale: In FIGO cervical cancer staging, tumor extension to the pelvic sidewall or causing hydronephrosis or non-functioning kidney is classified as Stage III.
-Stage 0 is carcinoma in situ, indicating a non-invasive stage.
-Stages I to III indicate progressively greater local spread within the pelvis, involving the cervix, parametria, and possibly causing obstruction or affecting adjacent structures.
-Stage IV indicates distant or invasive spread, involving organs like the bladder or rectum (Stage IVa) or metastasizing to distant parts of the body (Stage IVb).
- Presence of a midline septum that divides the uterus into two cavities is a result of:
A. Arrested Mullerian duct development
B. Failure of complete fusion of the Mullerian duct
C. Ipsilateral renal agenesis
D. Recurrent abortion
B. Failure of complete fusion of the Mullerian duct
Rationale: The presence of a midline septum dividing the uterus into two cavities results from incomplete fusion of the Mullerian ducts during embryogenesis, leading to a septate uterus.
- What is the implication of the Breast Imaging Reporting and Data System (BI-RADS) Category 3 score?
A. Need additional imaging evaluation and/or prior mammograms for comparison
B. Patient should return for routine screening
C. Probably benign, initial short interval follow-up suggested
D. Suspicious abnormality; biopsy should be considered
C. Probably benign, initial short interval follow-up suggested
Rationale: BI-RADS Category 3 indicates a lesion that is likely benign (<2% chance of malignancy) but requires short-term follow-up (typically 6 months) to confirm stability over time.
- Unicornuate anomaly of the uterus with a single fallopian tube is a result of:
A. Arrested Mullerian Duct Development
B. Failure of complete fusion of Mullerian duct
C. Infertility
D. Ipsilateral renal agenesis
A. Arrested Mullerian Duct Development
Rationale: Unicornuate uterus results from incomplete development of one of the paired Mullerian ducts during embryogenesis, leading to a single uterine horn and one fallopian tube.
- The most common well-defined solid mass seen on mammography is:
A. Fibroadenoma
B. Galactocele
C. Invasive ductal carcinoma
D. Simple cyst
A. Fibroadenoma
Rationale: Fibroadenomas are the most common benign solid masses seen on mammography, especially in younger women. They appear as well-defined, oval, and circumscribed lesions.
- The most common histologic type of endometrial carcinoma is:
A. Adenocarcinoma
B. Mucinous carcinoma
C. Sarcoma
D. Squamous carcinoma
A. Adenocarcinoma
Rationale: Endometrial adenocarcinoma is the most common histologic type of endometrial cancer, typically associated with unopposed estrogen exposure.
- Most patient with uterine leiomyomas present clinically as:
A. Asymptomatic
B. Excessive vaginal bleeding
C. Infertility
D. Pelvic pain
A. Asymptomatic
Rationale: Most patients with uterine leiomyomas (fibroids) are asymptomatic. When symptoms do occur, they may include excessive vaginal bleeding, pelvic pain, or infertility, but the majority of leiomyomas are incidental findings during routine pelvic exams or imaging for unrelated issues.
- The main indication of transvaginal ultrasound in pregnancy is:
A. Assessing fetal well-being
B. Evaluation of maternal pelvic organs
C. Assessment of first trimester pregnancy
D. Monitoring fetal growth
C. Assessment of first trimester pregnancy
Rationale: Transvaginal ultrasound is primarily used in the first trimester of pregnancy to evaluate the location, viability, and gestational age of the pregnancy. It provides a clearer image of early pregnancy structures compared to transabdominal ultrasound.
- What is the earliest fetal age when the normal gestational sac is seen on transabdominal ultrasound?
A. 3.5 to 4.5 menstrual weeks
B. 5 weeks menstrual age
C. 8 weeks menstrual age
D. 13 weeks menstrual age
B. 5 weeks menstrual age
Rationale: A normal gestational sac can typically be seen on transabdominal ultrasound starting at around 5 weeks of menstrual age. This early visualization helps confirm intrauterine pregnancy.
- Which of the following statements is true regarding the yolk sac?
A. Definitive ultrasound evidence of early pregnancy
B. Earliest site of neural cell formation in the embryo
C. Floats between the placenta and retroplacental tissues
D. Visualized within the gestational sac after the fetal pole
A. Definitive ultrasound evidence of early pregnancy
Rationale: The yolk sac is the first structure visible within the gestational sac that confirms an intrauterine pregnancy. It appears before the fetal pole and is an important marker in early pregnancy.
- Which of the following is a common cause of vaginal bleeding in the first trimester of pregnancy?
A. Anembryonic pregnancy
B. Intrauterine growth retardation
C. Placenta previa
D. Vasa previa
A. Anembryonic pregnancy
Rationale: Anembryonic pregnancy (also known as a blighted ovum) is a common cause of vaginal bleeding in the first trimester. It occurs when a gestational sac develops without an embryo.
VAGINAL BLEEDING IN THE 1ST TRIMESTER
* Spontaneous abortion
* Anembryonic pregnancy
* Embryonic demise
* Demise of a twin
* Ectopic pregnancy
* Subchorionic hemorrhage
* Implantation bleeding
* Gestational trophoblastic disease
- Which of the following is associated with ectopic pregnancy?
A. Double bleb sign
B. Pseudogestational sac sign
C. Corpus luteal cyst
D. Yolk sac in the uterine cavity
B. Pseudogestational sac sign
Rationale: A pseudogestational sac is often seen in ectopic pregnancy, which can mimic an intrauterine gestational sac but lacks the features of a true gestational sac, such as a yolk sac or fetal pole.
- Which of the following is true regarding partial hydatidiform mole?
A. Abnormal fetus
B. Diploid karyotype
C. Involves the entire placenta
D. Snowstorm appearance on ultrasound
A. Abnormal fetus
Rationale: A partial hydatidiform mole is characterized by the presence of an abnormal fetus with a triploid karyotype. The placenta also has abnormal cystic changes, but the mole is not completely invasive.
- Complete Mole: Characterized by involvement of the entire placenta, absence of a fetus, diploid karyotype, and classic snowstorm appearance on ultrasound. It often presents in the first trimester.
- Partial Mole: Involves only part of the placenta, may have an abnormal fetus, and has a triploid karyotype. It often presents in the second trimester and is characterized by discrete cystic vesicles on ultrasound.
- The crown-rump length is a measure of the fetus corresponding to:
A. Average diameter in three orthogonal planes
B. Ossified portion of the femoral diaphysis
C. Outer table of the near cranium to the inner table of the far cranium
D. Top of the head to bottom of the torso
D. Top of the head to bottom of the torso
Rationale: Crown-rump length (CRL) measures the length of the fetus from the top of the head (crown) to the bottom of the torso (rump), which is used for dating early pregnancy.
- The abdominal circumference is a measure of the fetus corresponding to:
A. Average diameter in three orthogonal planes
B. Outer perimeter at the level of the umbilical vein
C. Outer perimeter of the fetal cranium
D. Outer table to the inner table at the level of the third ventricle
B. Outer perimeter at the level of the umbilical vein
Rationale: Abdominal circumference is measured around the outer perimeter of the fetal abdomen, typically at the level of the umbilical vein and fetal stomach, and is used to assess fetal growth.
- The key parameter to evaluate in chronic hypoxia of the fetus is:
A. Amniotic fluid volume
B. Fetal tone and gross motor movements
C. Reactive fetal heart rate
D. Respiratory activity
A. Amniotic fluid volume
Rationale: In the biophysical profile (BPP), amniotic fluid volume is the key parameter for assessing chronic hypoxia in the fetus. A decreased amniotic fluid volume (oligohydramnios) can indicate long-term fetal hypoxia, as it reflects prolonged reduced blood flow to the placenta and fetal kidneys. Other parameters, such as reactive fetal heart rate, respiratory activity, gross motor movements, and fetal tone, are used to assess acute hypoxia.
Summary:
* The Biophysical Profile is used to assess fetal well-being by evaluating four parameters related to acute hypoxia (reactive fetal heart rate, respiratory activity, gross motor movements, and fetal tone) and one parameter related to chronic hypoxia (amniotic fluid volume).
* A normal BPP score suggests that the fetus is well-oxygenated, while a low score may indicate fetal compromise, requiring further intervention or monitoring.
- A thin placenta of less than 1 cm in thickness is commonly associated with:
A. Chronic uterine infection
B. Maternal anemia
C. Maternal diabetes
D. Trisomy 13 and 18
D. Trisomy 13 and 18
Thin Placenta (<1 cm)
-Preeclampsia
-Placental Insufficiency
-IUGR
-Trisomies 13 and 8
Thick Placenta (>4 cm)
-Maternal Diabetes
-Maternal Anemia
-Hydrops Fetalis
-Chronic Uterine Infection
- Which of the following is a risk factor for placenta previa?
A. Cocaine abuse
B. Maternal hypertension
C. Multiple previous pregnancies
D. Smoking
C. Multiple previous pregnancies
Rationale: Multiple previous pregnancies (multiparity) are a risk factor for placenta previa. The more pregnancies a woman has had, the greater the risk of abnormal placental implantation, such as placenta previa.
Risk factors:
* Scarring of lower uterine segment from previous CS
* Previous placenta previa
* Surgical scars
* Multiple previous pregnancies
- Which of the following is associated with polyhydramnios?
A. Anencephaly
B. Fetal renal anomalies
C. IUGR
D. Postdated pregnancies
A. Anencephaly
Rationale: Polyhydramnios is associated with fetal conditions that impair the ability to swallow amniotic fluid, such as anencephaly. It is also associated with gastrointestinal anomalies.
Fetal Anomalies:
* Anencephaly: A neural tube defect in which a major portion of the brain, skull, and scalp are absent.
* Encephalocele: A neural tube defect characterized by a sac-like protrusion of the brain and membranes through an opening in the skull.
* Gastrointestinal (GI) Obstruction: Conditions such as esophageal or duodenal atresia can prevent the fetus from swallowing amniotic fluid, leading to accumulation.
* Abdominal Wall Defect: Conditions like omphalocele or gastroschisis can be associated with polyhydramnios.
* Achondroplasia: A form of short-limbed dwarfism.
* Hydrops Fetalis: Severe fetal edema due to various underlying causes.
- Normal shape of the testicle on ultrasound:
A. Lambda
B. Ovoid
C. Rectangular
D. Hexagonal
B. Ovoid
Rationale: The normal shape of the testicle on ultrasound is ovoid. This shape helps to differentiate it from other scrotal masses or abnormalities.
- True of vascular flow of the testes on Doppler:
A. Symmetric
B. More on the right
C. More on the left
D. No flow
A. Symmetric
Rationale: Vascular flow of the testes is normally symmetric on Doppler ultrasound, with equal blood flow to both sides unless pathology is present.
- Deformity where Testis and Epididymis lack their normal attachment to the posterior wall of the scrotum:
A. Bell tower deformity
B. Bell shape deformity
C. Bell toll deformity
D. Bell clapper deformity
D. Bell clapper deformity
Rationale: The “bell clapper” deformity is a congenital condition in which the testis and epididymis lack their normal attachment to the scrotal wall, increasing the risk of testicular torsion.
- Percentage of testes salvaged if surgical correction of testicular torsion is done within 6 hours:
A. 80 to 90
B. 20 to 30
C. 60 to 70
D. 40 to 50
A. 80 to 90
Rationale: If surgical correction of testicular torsion is performed within 6 hours, 80-90% of the testes can be salvaged. The success rate decreases significantly with delayed intervention.
- Appearance of an infarcted testes:
A. Hypoechoic
B. Isoechoic
C. Hyperechoic
D. Heterogeneous
D. Heterogeneous
Rationale: An infarcted testis typically appears heterogeneous on ultrasound due to necrosis and loss of normal architecture. It may also show areas of decreased
echogenicity.
FEEDS: HYPOECHOIC
- Usual Doppler pattern of testicular torsion:
A. More than the contralateral side
B. Increased
C. Symmetric
D. Absent
D. Absent
Rationale: The usual Doppler pattern in testicular torsion is absent blood flow, indicating compromised perfusion due to twisting of the spermatic cord.
- Usual Doppler pattern of acute epididymo-orchitis:
A. Absent
B. Decreased
C. Increased
D. Symmetric
C. Increased
Rationale: Acute epididymo-orchitis is characterized by increased blood flow on Doppler ultrasound due to inflammation and hyperemia.
- Ultrasound findings of acute epididymitis:
A. Thinned out epididymis
B. Thickened epididymis with increased blood flow
C. Thickened epididymis with decreased blood flow
D. Absent epididymis
B. Thickened epididymis with increased blood flow
Rationale: Acute epididymitis typically presents with a thickened epididymis and increased blood flow, indicating inflammation.
- Most common cause of acute scrotum:
A. Testicular torsion
B. Acute epididymitis
C. Seminoma
D. Testicular cyst
B. Acute epididymitis
Rationale: Acute epididymitis is the most common cause of acute scrotum, especially in older children and adults. It presents with pain and swelling. Testicular torsion, although a surgical emergency, is less common compared to epididymitis.
- Accumulation of serous fluid between the visceral and parietal layers of the tunica vaginalis:
A. Pyocele
B. Hematocele
C. Hydrocele
D. Spermatocele
C. Hydrocele
Rationale: A hydrocele involves the accumulation of serous fluid between the visceral and parietal layers of the tunica vaginalis. It is typically painless and can be congenital or acquired.
- Most common cause of painless scrotal swelling:
A. Pyocele
B. Hematocele
C. Hydrocele
D. Spermatocele
C. Hydrocele
Rationale: Hydrocele is the most common cause of painless scrotal swelling. It results from fluid accumulation and can be either idiopathic or secondary to other conditions, such as trauma or infection.
