Skin and Soft Tissue

Question 1

Describe the normal anatomy and histology of the skin.

• layers
• adnexal structures
• glands and their locations

Answer 1

Normal skin includes dermal and epidermal layers as well as adnexal structures such as sweat glands (apocrine and eccrine), hair follicles, and sebaceous glands. Apocrine sweat glands, found primarily in the axilla, groin, and perineum, produce a cloudy, thick sweat associated with bacterial overgrowth and body odor, whereas eccrine sweat glands found on the rest of the body produce normal sweat to aid in temperature regulation.

Question 2

Basal cell carcinoma arises from…

Answer 2

…the basal cells in the innermost layer of the epidermis. These are the cells that continually divide to form the outer layers of the epidermis.

Question 3

Squamous cell carcinoma also arises from what layer of the skin…

Precursor lesion?

Answer 3

…in the epidermis but develops from squamous cells, which are keratin-producing.

Actinic keratosis, an overgrowth of keratinocytes, is a known precursor lesion for development of squamous cell carcinoma.

Question 4

Dermatofibrosarcoma protuberans is a cutaneous soft tissue sarcoma arising from…

Answer 4

…fibroblasts within the dermis. These tumors, which have a dermal origin, usually have a covering of epidermis.

Question 5

Cutaneous adnexal tumors are a wide variety of benign and malignant neoplasms that arise from…

Contrast benign and malignant types.

Answer 5

… sweat glands, hair follicles, and sebaceous glands.

Benign tumors are usually multilobulated and smooth-bordered, and histologically they have low mitotic rate, normal nuclei, and no ulceration.

In contrast, malignant tumors are more likely to be irregular and asymmetric, and they have high levels of nuclear atypia, a high mitotic rate, and ulceration.

Question 6

Merkel cell carcinoma is traditionally believed to arise from…

Answer 6

…neuroendocrine cells in the epidermis which function as mechanoreceptors, although some researchers believe that these tumors arise from stem cells which only later take on the neuroendocrine morphology.

Question 7

Basal cell carcinoma is the most common type of skin cancer and makes up about 80% of nonmelanoma skin cancers. About 20% of Americans will develop nonmelanoma skin cancer in their lifetime. Risk factors for developing basal cell carcinoma incude…

Answer 7

…ultraviolet light exposure; older age; fair skin; smoking; exposure to organic hydrocarbons, arsenic, or ionizing radiation; and immunosuppression.

Typically, the sun exposure has been intermittent and intense rather than chronic and moderate.

Question 8

Squamous cell carcinoma is the second most common skin cancer, making up approximately 20% of nonmelanoma skin cancers. Risk factors for developing squamous cell carcinoma, which are similar to the risk factors for developing basal cell carcinoma, include…

Answer 8

… prolonged ultraviolet light exposure, older age, fair skin, nonhealing wounds with chronic inflammation, smoking, chemical and radiation exposure, and human papilloma virus infection.

Most common type of skin cancer seen in transplant patients.

Question 9

Dermatofibrosarcoma protuberans epidemiology

Answer 9

rare nonmelanoma skin cancer, with fewer than 5 cases per million per year. It presents more commonly in younger patients (average age at diagnosis, mid-30s) and is more common in African Americans than Caucasians.

Question 10

Cutaneous adnexal tumors epidemiology

Answer 10

Rare. Malignant cutaneous adnexal tumors typically present in older patients with a median age of 70 years, whereas benign lesions more commonly present in the fourth to sixth decades of life.

Question 11

Merkel cell carcinoma epidemiology

Answer 11

• Rare tumor, with about 6 cases per million per year in the US.
• Present in older pts with a median age at presentation of 70.
• Risk factors for developing Merkel cell carcinoma: UV light, fair skin, immunosuppression, which is a critical risk factor, and a history of leukemia and lymphoma.
• Merkel cell polyomavirus seems to play a role in the tumorigenesis of most Merkel cell carcinomas, although many patients who carry the virus do not go on to develop Merkel cell carcinoma.

Question 12

The history of the nonmelanoma skin lesion itself should focus on…

Answer 12

…time course, growth, prior trauma to the area, history of previous similar lesions, associated symptoms such as pruritus or pain, and any previous treatments or procedures in the area.

Question 13

Exposure history should focus on…

Answer 13

…known risk factors for skin cancer, with a particular emphasis on sun exposure (occupational or recreational), tanning bed use, and radiation or chemical exposure. In addition, patients with a history of prior skin cancers are at an increased risk for subsequent skin cancers.

Question 14

In addition to careful examination of the nonmelanoma skin lesion itself, the physical examination should note:

Answer 14

• The presence of any abnormalities of the surrounding skin (such as satellite lesions)
• The presence or absence of ulceration
• Whether the lesion is fixed to underlying structures
• Draining lymph nodes

Question 15

Several adnexal skin tumors, which are rare in the general population, may be common in patients with certain genetic syndromes such as,..

Answer 15

Brooke-Spiegler syndrome, Birt-Hogg-Dubé syndrome, Muir-Torre syndrome, Cowden syndrome, familial cylindromatosis, and multiple familial trichoepithelioma.

Question 16

Squamous cell carcinoma physical exam

Answer 16

• arises in a background of actinic keratosis—scaly and erythematous lesions in sun-damaged areas
• the squamous cell carcinoma itself is often ulcerated with raised edges.

Question 17

Basal cell carcinomas physical exam

Answer 17

• have some diversity in appearance and come in nodular, cystic, superficial, micronodular, and morpheaform patterns
• most commonly, they are raised, well-circumscribed, and waxy, classically with “rolled” or “pearlescent” edges.

Question 18

Dermatofibrosarcoma protuberans typically presents…

Answer 18

• initially as a plaque or nodule covered with skin, which may initially be normal
• more advanced tumors will be larger and more protuberant and more typically demonstrate overlying skin changes

Question 19

Cutaneous adnexal tumors typically present with…

Answer 19

…pink or skin-colored nodules less than a few centimeters in size. Ulceration may indicate malignancy.

Question 20

Merkel cell carcinoma typically presents as…

Answer 20

…a firm bump within the skin which grows quickly and is typically a red/purple nodule without ulceration.

Question 21

Determine the appropriate technique of biopsy of a suspicious skin lesion (types of biopsies).

Punch biopsy.

Answer 21

Performed under local anesthesia, a full-thickness sample of the tumor ideally with a border of normal surrounding skin.

Question 22

Extra workup?

• dermatofibrosarcoma protuberans with fibrosarcomatous
• higher risk Merkel cell carcinoma

Answer 22

• Chest CT to evaluate for distant metastasis.
• Merkel cell carcinoma has a high propensity to metastasize, and staging PET scan or CT scans should be considered in higher risk cases.

Question 23

Basal cell carcinoma and squamous cell carcinoma should usually be excised with margins of…

Answer 23

… 4 to 10 mm, depending on tumor risk profile.

Question 24

Dermatofibrosarcoma protuberans should usually be excised with wide margins of…

Answer 24

2 to 4 cm because rates of local recurrence are higher with narrower margins.

Question 25

Cutaneous adnexal tumors that are benign may undergo what type of excision?

If these tumors are malignant, they should be…

Answer 25

• Simple excision if they are symptomatic or cosmetically undesirable, but they may be observed in some cases, depending on histology.
• … widely excised w/ 1 - 2 cm margin, consider SLNBx

Question 26

Merkel cell carcinoma operative approach?

Answer 26

should be widely excised with 1 to 2 cm margins

consider SLNBx (high rate of nodal mets)

Question 27

Sentinel lymph node biopsy in nonmelanomatous skin cancers

• What situations warrant SLNBx?
• What if biopsy is positive?
• What if clinically apparent lymph node disease?

Answer 27

SLNBx not routine for many types of nonmelanoma skin cancers

• High-risk SCC, malignant cutaneous adnexal tumors, MCCa
• Completion lymphadenectomy considered with positive SLNBx
• Clinically apparent LN dz may benefit from a therapeutic lymphadenectomy

Question 28

Mohs surgery relies on serial frozen section analysis of margins and for specific types of nonmelanoma skin cancer may permit comparable oncologic outcomes without the need for large tissue defects. What situations warrant its use?

Answer 28

It is considered for specific types of skin cancers such as basal cell carcinoma and squamous cell carcinoma, particularly for tumors on the head or neck, or for tumors in which reconstruction of a large tissue defect is impractical.

Question 29

Premalignant lesions such as actinic keratosis nonop management option

Answer 29

Topical therapies such as imiquimod or 5-fluorouracil may be used in some cases

Question 30

Low-risk, small, squamous cell carcinomas or basal cell carcinomas are sometimes successfully treated with…

Answer 30

cryotherapy, laser ablation, or electrodesiccation

Question 31

A 75-year-old man, a retired highway worker, presents to your office with a raised and ulcerated plaque on his left cheek. It has been present and gradually growing for the past 6 months. How would you work up this patient? What will your management be?

Answer 31

• Suspicious for cutaneous squamous cell carcinoma, maintain a broad differential diagnosis (basal cell carcinoma, atypical melanoma, and cutaneous adnexal tumor)
• Punch biopsy is test of choice after H&P
• If the patient is an appropriate candidate based on histologic type of tumor (eg, squamous cell carcinoma or basal cell carcinoma) and clinical parameters, Mohs surgery should be considered in lieu of traditional wide local excision, given the location of the lesion (on the face).

Question 32

A 40-year-old African American man in good health presents to your office for consultation after biopsy of a raised lesion on his left flank comes back as dermatofibrosarcoma protuberans. How do you manage this case? How would your management change if the pathologist’s report also noted fibrosarcomatous change?

Answer 32

• Wide excision w/ 2-4cm margins, high rate of local recurrence.
• Fibrosarcomatous change on pathology should trigger a more extensive staging workup, such as CT scan of the chest, because these tumors are much more likely to metastasize. High-risk may benefit from adjuvant or neoadjuvant therapy.

Question 33

You see a 62-year-old woman in your office for her postoperative visit after removing a 2-cm basal cell carcinoma from her right shoulder. She would like to know why she developed this tumor and what she can do to prevent another one from occurring. What do you tell her?

Answer 33

The most important modifiable risk factor for nonmelanoma skin cancer is sun exposure.

Potentially modifiable risk factors for nonmelanoma skin cancer include occupational chemical or radiation exposure, chronic wounds, and smoking.

Nonmodifiable risk factors include immunosuppression, age, and skin type.

Question 34

A 77-year-old white male presents to your office with a firm 1-cm intradermal nodule on his left shoulder which has been growing quickly. Punch biopsy is performed and pathology reveals nests of small blue cells. What is the likely diagnosis and how will you manage and counsel this patient?

Answer 34

• Merkel cell carcinoma.
• Wide local excision with 1-2 cm margins and often sentinel lymph node biopsy.
• Pre-operative staging w/ PET or CT scans based on risk profile.
• Adjuvant radiation may be considered, relatively high rates of recurrence.
• The recurrence rate for Merkel cell carcinoma is relatively high, and patients require frequent follow up and surveillance.

Question 35

Targeted therapies such as vismodegib can be used in what type of skin cancer when it has become metastatis?

Answer 35

basal cell carcinoma

Question 36

Epidermal growth factor antagonists or tyrosine kinase inhibitors can be used for what skin cancer if it has become metastatic?

Answer 36

squamous cell carcinoma

Question 37

has shown some efficacy in locally advanced or metastatic dermatofibrosarcoma protuberans

Answer 37

Imatinib

Question 38

is a therapeutic option for patients who develop distant metastases from Merkel cell carcinoma.

Answer 38

immunotherapy

Question 39

Adjuvant radiation therapy may be used in which settings in regards to skin cancer

Answer 39

dermatofibrosarcoma protuberans, in high-risk cases, with positive margins in which additional surgery is not feasible

the resection bed or nodal basin in Merkel cell carcinoma

may be considered as the primary therapy for patients with Merkel cell carcinoma who cannot undergo appropriate resection due to comorbidities

Question 40

Albinism or xeroderma pigmentosum are associated with development of what types of skin cancers?

Answer 40

Sun-related cancers such as basal cell or squamous cell carcinoma.

Question 41

Individuals with may develop dozens of basal cell carcinomas as well as bony cysts, medulloblastoma, and craniofacial abnormalities, a disorder known as basal cell carcinoma syndrome.

Answer 41

germline mutations in the PTCH1 gene

Question 42

Determine the appropriate technique of biopsy of a suspicious skin lesion (types of biopsies).

Excisional biopsy

Answer 42

Excisional biopsy removes the entire lesion in the initial specimen. Care must be taken in the initial approach (eg, orientation of wound and amount of tissue removed) to plan for a potential reexcision in case the final pathology requires definitive surgical treatment.

Question 43

Determine the appropriate technique of biopsy of a suspicious skin lesion (types of biopsies).

Core needle biopsy or incisional biopsy

Answer 43

Core needle biopsy or incisional biopsy may be considered in patients who have deeper or larger tumors such as dermatofibrosarcoma protuberans.

Question 44

Determine the appropriate technique of biopsy of a suspicious skin lesion (types of biopsies).

Shave biopsy

Answer 44

Shave biopsy is often inadequate for differentiating between the various entities under consideration when working up a potential cutaneous malignancy.

Question 45

Determine the appropriate technique of biopsy of a suspicious skin lesion: reason/use for histologic analysis.

Answer 45

Routine histologic analysis provides some information about the architecture and possible cellular lineage of the tumor, but special stains or even genetic analysis may help distinguish among some types of tumors. These are particularly useful in cases of cutaneous metastases from nonskin cancers.

Question 46

Risk factors for surgical site infection:

Answer 46

• patient: age, obesity, DM, low nutrition, radx, low O2
• environmental: poor sterilization, ventilation
• treatment: emergent procedures, prolonged OR time, inadequate abx

Question 47

What are the 4 wound classes?

Answer 47

1. clean - no entry of respiratory, GI, GU tracts; no inflammation
2. clean contaminated - entry of respiratory, GI, GU tract w/ minimal spillage; no infected fluids; minor break in technique
3. contaminated - gross spillage of infected fluid from respiratory, GI, GU tracts; fresh trauma; major break in technique
4. dirty - acute bacterial inflammation, devitalized tissue, FB, fecal contamination, delay in treatment

Question 48

How can you optimize patient factors in a pre-op patient the day before and day of surgery to prevent surgical site infections?

Answer 48

• patient should bathe fully the night before
• alcohol-based prep unless contraindicated
• remove hair with clippers
• control glucose
• control temperature

Question 49

What three factors determine prophylactic antibiotic choice in elective procedures?

Answer 49

• type of surgery
• antibiotic allergies
• presence of MRSA

Question 50

Control glucose in postop patients between what levels?

Why?

Answer 50

140 - 180

>200 increases risk of SSI

Question 51

How is SSI diagnosed?

Answer 51

• the diagnosis is clinical
• vitals: can have tachycardia, tachypnea, or fever
• exam: erythema, induration, fluctuance, warmth
• labs: elevated WBC, elevated bands
• cultures are not required for dx, but may aid in abx tailoring in deep or organ space level infections

Question 52

Given a patient with an organ/space SSI, manage the patient.

Answer 52

• ABC - resuscitate if necessary
• Obtain blood cultures
• Broad spec abx - zosyn, mero, cefepime+flagyl
• IR drainage vs open - source control + cultures
• Continue abx 4 days after surgically cleared

Question 53

A 78-year-old man with a history of diabetes and hypertension is about to undergo a left colectomy for colon cancer. How will you prepare him for surgery?

Answer 53

• bathe night before
• postop glucose control
• ppx abx (ancef + flagyl, vanc + levaquin), bowel prep
• clippers, avoid hypothermia, alcohol skin prep

Question 54

One week after laparoscopic appendectomy, a 28-year-old woman comes to your office complaining of diarrhea, fever, and lower abdominal pain. What will you do?

Answer 54

• possible pelvic abscess
• rectal/pelvic exam
• labs, CT abd/pelvis
• zosyn + drain

Question 55

How does a pilonidal abscess typical present?

Answer 55

erythema, tenderness, fluctuance, drainage at the intergluteal cleft

Question 56

Does the abscess in pilonidal disease have an epithelial lining? What is contained in the abscess?

Answer 56

No. It is a subcutaneous abscess filled with hair, debris, and purulent material.

Question 57

How is a pilonidal sinus different from a pilonidal abscess?

Answer 57

The sinus is a tract draining cranially and laterally from the cleft in the setting of chronic pilonidal disease.

Question 58

Describe the management of a pilnidal abscess?

Answer 58

Outpatient I&D with a paramidline incision, soak in warm tub multiple times/day.

Question 59

Describe the management of a pilonidal sinus.

Answer 59

Outpatient unroofing - use a probe and direct it into the lowest portion of the sinus. Use electrocautery to open sinus over the probe. Connect all pits and sinuses. Curette tract to remove debris and marsupialize the edges of the wound.

The tract can also be excised down to sacrococcygeal fossa and primarily closed if no infection/contamination or can be left open and packed. If the tract is large, you can flap over the wound. The goal of the flaps is to make the intergluteal cleft more shallow.

Question 60

Dictate the a pilonidal sinus excision.

Answer 60

The patient was identified in preop, consent and procedure confirmed, then taken to the OR. General anesthesia was induced, and the patient was placed in the prone position. The patient was prepped and draped in the standard fashion (buttocks spread and held open with adhesive tape) and a timeout was called. The planned paramidline elliptical incision was made to include all of the sinus, including the lowest portions. The tissue was excised down to the sacral fascia. Because there was no infection or debris encountered, the resulting wound was closed primarily.in layers.

Question 61

What counseling for the nonoperative portions of management can you provide a patient with pilonidal disease?

Answer 61

• keep hair short
• perineal hygiene is important
• laser hair-removal can provide long-lasting hair removal

the above results in fewer hospital admissions and surgical procedures for this population

Question 62

Comment on the postop course of pilonidal disease?

Answer 62

wounds often break down and reoperation rate is around 50%; healing takes a long time

Question 64

What is a recognized risk factor for development of sarcoma, resulting in an 8- to 50-fold increased incidence? Other sarcoma causes?

Answer 64

External-beam radiation therapy. Radiation-associated sarcomas have a poor prognosis.

Chemicals such as phenoxyacetic acid and chlorophenols increase the risk of soft tissue sarcomas. Also, exposure to thorium oxide, vinyl chloride, and arsenic are associated with hepatic angiosarcomas.

Chronic lymphedema after axillary dissection increases the risk of lymphangiosarcoma (Stewart-Treves syndrome). Several genetic conditions are associated with an increased risk of sarcoma, including Li-Fraumeni syndrome, neurofibromatosis type 1, familial adenomatous polyposis, and retinoblastoma.

Question 65

Imaging for soft tissue masses?

Answer 65

Ultrasound is often a good first imaging modality to evaluate a new soft tissue mass. It may also be considered for superficial lesions, particularly of the extremities, neck, or abdominal wall.

[CT] or [MRI] may be necessary to determine relationships to surrounding structures, especially usefol for the abdomen, pelvis, and retroperitoneum.

MRI is preferred for extremity lesions because of its better characterization of muscular and neurovascular structures.

Question 66

What distinguishes lipomas from well-differentiated liposarcoma?

Answer 66

Amplification of MDM2 on biopsy or excision specimens

Question 67

Determine whether biopsy is necessary for soft tissue sarcomas and, if so, determine the appropriate type of biopsy.

Answer 67

Core needle biopsy is preferred over fine needle aspiration. Excisional biopsy is appropriate for masses less than 5 cm on the extremities or superficial lesions on the trunk.

For extremity and truncal tumors, the biopsy site should be in line with the planned incision for tumor removal because the biopsy track should be excised with the tumor. The excisional biopsy ellipse should be longitudinal (not transverse) along the extremities in order to minimize skin and soft tissue loss during tumor resection.

Question 68

When is it ideal to do an excisional biopsy for a suspected soft tissue sarcoma?

Answer 68

If the mass is superficial, located on the trunk or extremity and less than 5 cm, excisional biopsy is appropriate. Deeper masses and those greater than 5 cm may require incisional biopsy and appropriate cross-sectional imaging to assess resectability.

Question 69

Given the diagnosis of a benign or cystic mass, understand the recommended strategy for removal.

Answer 69

Enucleation inclusive of the capsule ensures the lowest likelihood of recurrence or reaccumulation of cystic matter.

Question 70

Based on appropriate imaging studies, determine whether a soft tissue sarcoma is operable and describe the operative approach. Consider management of adjacent structures and adequate closure.

Answer 70

Generally, 1- to 2-cm margins (if possible) are desired. However, narrower margins are acceptable if achieving them would result in major neurovascular compromise.

Neoadjuvant radiation should be considered and discussed at a multidisciplinary tumor board prior to surgery, especially if the sarcoma is in close proximity to neurovascular structures or a narrow margin is expected.

Question 71

What retroperitoneal/abdominal sarcomas are unresectable?

Answer 71

Sarcomas with critical vascular involvement, peritoneal implants, involvement of the root of the mesentery, or spinal cord involvement are usually considered unresectable.

Question 72

In a patient presenting with a potentially resectable sarcoma, identify those situations where lymphadenectomy or sentinel lymph node biopsy should be considered.

Answer 72

Patients with clinically or radiologically suspicious nodes should undergo fine needle aspiration or core biopsy prior to lymph node dissection.

For proven regional lymph node metastasis, radical lymphadenectomy is the treatment of choice and may improve survival.

Question 73

For resectable extremity or truncal sarcomas, describe when to consider neoadjuvant or adjuvant radiation therapy (RT).

Answer 73

High-grade sarcomas and tumors greater than 5 cm in size should be considered for RT to decrease local recurrence.

The benefits of neoadjuvant (preoperative) RT include (1) smaller treatment field because it targets the in situ tumor, (2) lower total radiation dose, (3) shorter course of treatment, and (4) potential downstaging of borderline resectable tumors allowing limb salvage. However, neoadjuvant radiation predisposes to wound complications.

Current chemotherapy agents are not highly effective for sarcomas.

Question 74

For biopsy-proven desmoid tumors (aggressive fibromatosis), describe a management plan.

Answer 74

For patients with asymptomatic, resectable desmoids, the current recommendation is to start with a “wait and see” approach—an initial period of surveillance with imaging every 3 months in order to demonstrate tumor stability/regression or progression. This should not be done for tumors that would result in functional limitations if the tumor increased in size.

For progressing desmoids, consider systemic therapy, resection, or RT, depending on location and surgical morbidity. Systemic agents to consider are tamoxifen with or without sulindac, sorafenib, and liposomal doxorubicin.

Surgical resection may be considered in cases of low surgical morbidity, significant symptoms, and locations with lower risk of recurrence (abdominal wall).

Question 75

In a patient presenting with a soft tissue sarcoma determined to be unresectable on initial evaluation but without distant metastases, establish an alternate treatment plan.

Answer 75

For unresectable soft tissue sarcomas of the extremity, treatment options include RT, chemoradiation, chemotherapy alone, or regional limb therapy.

Reassessment after initial therapy for resectability should occur. If resectable, pursue surgery for adequate margins. If unresectable, consider palliative options, which may include amputation or chemotherapy, RT, or both, or supportive care based on the patient’s wishes.

For unresectable sarcomas of the abdomen/retroperitoneum, attempt downstaging with chemotherapy, radiation, or combined therapy with reassessment for resection, or definitive nonoperative treatment with chemotherapy and/or RT. Palliative debulking surgery is generally not recommended.

Question 76

In a patient who presents with a metastatic recurrence after treatment of a soft tissue sarcoma, describe when surgical resection of the metastatic disease is appropriate.

Answer 76

For regional recurrence or lymph node recurrence, regional lymph node dissection and/or metastasectomy followed by chemotherapy with or without RT should be pursued. Isolated limb therapy may also be warranted, depending on provider and institution comfort/experience.

For disseminated disease, palliative surgery could be considered for particular symptomatic control (small bowel bypass, ostomy, drain placement); debulking is generally not recommended. Palliative chemotherapy and/or RT is appropriate with supportive care. Ablation and embolization procedures may be considered.