1. Skin tumors…examples
The main risk factor for the tumors in boxes is sun exposure (among others)
and lightly pigmented individuals are more at risk
Remember xeroderma pigmentosum
patients and their tendency for malignant
skin tumors
Epidermal tumors
Adnexal tumors
Melanocytic tumors
Dermal tumors
SCC in situ
-Squamous cell carcinoma (SCC)
-Basal cell carcinoma (BCC)
Melanoma
(the benign counterpart is nevus...epidermal, intradermal, junctional or compound)
Actinic keratosis
Basal cell layer atypia (dysplasia) with risk to transform into SCC in situ & SCC (just a risk…not always)

2. Invasive SCC A nodule or non-healing ulcer
Any site on the face and others, especially sun-exposed

3. BCC The most common cancer worldwide Sometimes ulcerated: rodent ulcer
…due to telangiectatic vessels in the dermis
Commonly found on the face above
a line drawn from the angle of the mouth to the lobe of the ear
Most basal cell carcinomas have mutations
that lead to unbridled Hedgehog signaling (like mutations of the tumor suppressor PTCH)
Non-metastasizing but locally destructive
and occasionally can be disfiguring
What is Gorlin syndrome?

4. *Melanoma:
-Asymmetry
-Border irregularity
-Variation in color
-Large size
*Remember in melanoma pathogenesis:
Radial growth (inside the epidermis) then vertical growth then metastasis

5. Features of melanoma

6. The main 4 types of melanoma
Sun-exposed areas
The main 4 types of melanoma

7. Intradermal nevus (the most common type of nevus)
Epithelioid benign cells
maturation
In melanoma: in addition to
atypia and deep and epidermal
invasion, the maturation is lost
Remember that giant congenital hairy nevus and dysplastic nevus
carry some risk of transformation into melanoma
Lymphocyte-like benign cells
Spindle benign cells
Visit for references

8. (Benign)
(Malignant)
(Benign)
(Malignant)

9. The most common soft tissue tumor of adulthood
*Lipoma:
-well-circumscribed
-homogenous
-fatty cut surface
-soft
The most common soft tissue tumor of adulthood
visit for references
…usually arises in the subcutis of the proximal extremities and trunk, most frequently during middle adulthood

10. Bland-looking nuclei…small and at the periphery
Mature fatty tissue
*Lipoma
Bland-looking nuclei…small and at the periphery
Large one fat vacuole
Visit for references

11. Liposarcoma Large Firm to hard Fleshy
Heterogenous cut surface
Fixed to the skin and may ulcerate
One of the most common sarcomas of adulthood
Liposarcoma
…mainly in people in their 50s to 60s in the deep soft tissues of the proximal extremities and in the retroperitoneum
Note the enlarged nuclei with
hyperchromasia and marked pleomorphism

12. Bland-looking spindle nuclei that infiltrates surrounding structures such as muscle
Skeletal muscle fiber
Fibromatosis

13. Same as previous slide

14. *An example of superficial fibromatosis
*Another example of superficial fibromatosis is peyronie's disease of the penis (curved, painful erections)
*Desmoid tumor is an example
of deep fibromatosis
…abdominal wall is most common
…may follow pregnancy

15. UPS (undifferentiated pleomorphic sarcoma)
an abnormal mitosis
a bizarre cell
UPS (undifferentiated pleomorphic sarcoma)
…as its name indicates
-The most common sarcoma in adults
-Most arise in the deep
soft tissues of the extremity, especially the thigh of middle
aged or older adults

16. Bone tumors…examples Bone-forming tumors Cartilage-forming tumors
Tumors of unknown origin
Metastases
ABC
Osteosarcoma (malignant)
Osteochondroma (benign)
Chondrosarcoma (malignant)
Ewing sarcoma family tumors (malignant)
Giant cell tumor (benign)
Chondroma/enchondroma
(benign)
= “secondary bone tumors”
..the most common malignant
bone tumor
Primary bone tumors
Aneurysmal bone cyst:
-consists of multiloculated
blood-filled cystic spaces
-can be a 1ry tumor or a reaction to certain bone tumors

17. Osteochondroma = “Exostosis”
-The most common benign bone tumor
-85%: solitary (late adolescence
and early adulthood)
…the remainder: multiple hereditary exostosis syndrome
-Most commonly: metaphysis of
long bones especially around the
knee
-slow-growing masses
-can be painful if they impinge
on a nerve or if the stalk is
fractured
-In many cases they are detected
incidentally
-Osteochondromas usually stop growing
at the time of growth plate closure
Cartilage cap that remained
after ossification of the part proximal
to original bone
The cartilage cap resembles
a disorganized growth plate
Stalk with a cavity continuous
with original bone cavity
Unremarkable bone & bone marrow
5-20% progress to chondrosarcoma

18. Chondroma/Enchondroma
If central (medullary)
*Age: 20s-50s
*Hand and foot bones are most common
*Mainly metaphysis
Ollier disease and Maffucci syndrome
…multiple enchondromas
…more risk for progressing to chondrosarcoma

19. Osteosarcoma Characteristic, but not only here
Due to breaking through cortex and periosteum lifting, a reactive bone formed a triangle (Codman triangle)
Lace-like osteoid is characteristic
Osteoid directly formed by
malignant cells...may be mineralized later
Pleomorphic cells and abnormal mitoses

20. Osteosarcoma *The most common site: around the knee
*The most common primary malignant tumor of bone,
exclusive of myeloma and lymphoma
*The most common site: around the knee
*Bimodal age distribution:
…mostly: <20 year old
…a smaller ratio: older adults (commonly due to an
underlying condition)
*Males more than females
…typically: painful, progressively enlarging masses …sometimes a sudden fracture of the bone is the first symptom
*Remember that the fracture due to trivial trauma
because of bone disease is called: pathological fracture
*Common genes affected:
-RB…70% of sporadic cases
-TP53
-INK4a…encodes 2 tumor suppressors (p16 (inhibitor of cyclin-dependent kinases) & p14 (augments p53 function))
-MDM2 (inhibitor of p53) & CDK4 (inhibitor of RB)
*Hematogenous spread…especially to the lung
*Recurrent, metastatic and secondary osteosarcomas have
worse prognosis
Chemotherapy + Surgery

21. Chondrosarcoma
*The most common subtype is: conventional chondrosarcoma
*Mostly central (intramedullary)
*Axial skeleton more, especially the pelvis
*The 2nd most common malignant matrix-producing tumor
*Usually as a painful, progressively enlarging masse

22. Ewing sarcoma family tumors
…one of the small round blue cell tumors
Ewing sarcoma family tumors
*Recently, Ewing sarcoma and primitive neuroectodermal tumor (PNET) have been unified into a single category: the Ewing sarcoma family tumors (ESFT)
*The second most common group
of bone sarcomas in children
…a striking predilection for whites; blacks and Asians are rarely afflicted
…mainly diaphysis of long bones, especially femur
EWS gene (on chromosome 22) rearrangements
*The characteristic periosteal reaction produces layers of reactive bone deposited in an onion-skin fashion

23. Giant cell tumor (= “Osteoclastoma”)
*Age: 20s-40s
*Rare
*Benign but locally aggressive
…mainly the epiphysis of long bones
*The background mononuclear cells are the neoplastic cells here

24. Thank You