#dermpathjc November 2018:

 

Journal Club Summary:

Topics Discussed:

 Variants of cutaneous SCC:

1. 1. Squamous cell carcinoma (NOS)
   2. Keratoacanthoma*
   3. Verrucous SCC*
   4. Acantholytic SCC
   5. Adenosquamous SCC
   6. Spindle cell SCC
   7. Rare variants (Lymphoepithelial-like SCC, Pseudovascular SCC, and SCC with sarcomatoid differentiation)

*These low-grade variants can be locally destructive but have little potential to metastasize

Basal Cell Carcinoma:

1. Lower Risk: Superficial, nodular, pigmented, infundibulocystic, Fibroepithelioma of Pinkus
   • Fibroedpitheloma of Pinkus, aka Pinkus tumor renamed as fibroepithelial basal cell carcinoma
2. Higher Risk: Micronodular, infiltrating, morpheaform/sclerosing, basosquamous carcinoma, BCC with sarcomatoid differentiation
   • Micronodular: irregular, infiltrative deep/peripheral edges. Defined as >50 small nodules (<0.15 mm in diameter)
   • Infiltrating: Small irregular/jagged nests, at least 5-8 cells thick at least
     1. In contrast, Dr. Singh explained that morpheaform can be less than 5 cells thick. “In short, morpheaform tends to have smaller basaloid nests. But to stress again many consider them as same of overlapping features.”
     2. Others commented that in the morpheaform subtype they also look for dense fibrous/keloid-like collagen fibers

Basosquamous: Zones contain cells with intermediate features between the two. The basaloid component stains positive for BerEP4 and the squamous areas express MUC1 (EMA)

Melanocytic Tumors:

• This new approach to melanoma classification was appreciated by many in the Dermpath JC twitter community as there is a higher emphasis on the chronicity of sun damage and how it impacts certain pathways in melanoma progression.
• Two main pathways CDKN2A pathway and the MAPK pathway were discussed.

 

Dysplastic Nevi:

Low Grade: Moderate cytologic and architectural atypia

High Grade: Severe cytologic and architectural atypia

BAPOMA: Combined nevus with a benign nevic component and almost a spitzoid component. Some spitz like areas show multinucleation with an admixed infiltrate.

BAP1 lost especially present in the larger cells. BRAF mutations mostly also seen.

 

New Entities:

1. Endocrine mucin producing sweat gland carcinoma
   • Low-grade neuroendocrine neoplasm
   • Predilection for eyelid and periorbital skin. However, occurrence in an extrafacial location has also been reported.
   • Precursor of mucinous carcinoma
   • Older individuals (i.e. in the sixth and seventh decades of life)
   • Positive for CK7, CK8, CK18, AE1/AE3, CAM5.2, EMA, GCDFP15, WT1, ER and PR. Intensity for chromogranin and synaptophysin varies. Ki-67 is low.
2. Squamoid eccrine ductal carcinoma
   • Present as large nodules and plaques in the head and neck area.
   • Positive for cytokeratin and ductal differentiation can be confirmed by MUC1 and CEA.
3. Secretory carcinoma of the skin
   • Axillary location.
   • Rare sites include the face (including the lips), trunk, and limbs.
4. Signet ring cell/histiocytoid carcinoma
   • Males>females
   • Predilection for eyelids, but identical neoplasms have been reported in the axilla.
5. Hematolymphoid tumors
   1. CD30 lymphoproliferative disorders
      • Types A-C morphologic criteria remain the same.
      • Type D: shows epidermotropic infiltrates of CD8+ and CD30+ atypical cells and mimics primary cutaneous aggressive epidermotropic CD8+ cytotoxic T-cell lymphoma.
      • Type E: characterized by angiocentric and destructive infiltrates, predominantly medium sized atypical CD30+ lymphocytes with extensive dermal necrosis and ulceration.
   2. Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder
      • Solitary skin lesion, and no evidence of the patches or plaques.
      • Ulcer/papules show spontaneous regression.
      • Expression of PD-1(follicular T-cell marker), monoclonality of T-cell receptor (60%).
      • Similar phenotype has been observed in patients with multiple lesions. This is still an understudied area and it is important to recognize for therapeutic options and to determine prognosis.

Soft tissue tumors:

1. New Entities
   • Pseudomyogenic (epithelioid sarcoma-like) hemangioendothelioma
     1. Spindled to epithelioid, rarely metastasizing neoplasm
     2. Mimics myotid tumor or epithelioid sarcoma
     3. SEPINE1-FOSB fusion
     4. Male predominance
     5. Lower extremities > upper extremities or trunk
     6. FOSB consistently positive
   • Cutaneous leiomyosarcoma
     1. Prognosis of these tumors is superb, no metastases
     2. Grading is not of prognostic value
   • Angiosarcoma
   • Majority associated with radiation or preexisting lymphedema are associated with MYC gene amplification and co-amplification of FLT-4.
     1. This may be helpful in cases where MYC amplification is not seen.

 

 Special thanks to Dr. Singh (@mydermpath) for putting the presentation together and to the @DermpathJC twitter community for another successful discussion.

 The detailed slides/summary and accompanying virtual images can be accessed here:

 Pathpresenter.net

Login: pp@gmail.com

Password: welcomepp

Click on: My presentations

Click on DermpathJC

 Here are the corresponding diagnoses to the online virtual images: 

1. Keratoacanthoma
2. Verrucous carcinoma
3. Micronodular basal cell carcinoma
4. Morpheaform BCC
5. Infiltrative bcc
6. Bapoma
7. Trichoblastic carcinoma
8. Secretory carcinoma
9. Endocrine mucin producing sweat gland carcinoma
10. Signet ring/histicocytoid carcinoma
11. Squamoid eccrine carcinoma
12. CEA
13. Adnexal adenocarcinoma NOS
14. Leiyomyosarcoma
15. Pseudomyogenic hemangioendothelioma
16. Epithelioid histiocytoma
17. Type E LYP
18. Erdheim Chester Disease
19. Conjunctival melanoma
20. Conjunctival primary acquired melanosis
21. Conjunctival nevus

 

Thanks to all who participated! See you in December! Save the date 12/27/2018, 9pmEST.

Kind regards,

Silvija Gottesman, MD