Differential Diagnosis for Cutaneous Masses Flashcards

1
Q

Benefits of FNA/FNCS

A

Quick
Simple
Cheap
Possible to do in-house
Helpful in establishing diagnosis

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2
Q

Possible outcomes of cytological findings

A

Arrive at definitive diagnosis
Investigate further
Leave mass alone

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3
Q

What can cytology tell us about a mass?

A

Inflammatory
○ Septic
○ Sterile
Non-inflammatory
○ Cystic
○ Hyperplastic/dysplastic
○ Neoplastic
* Round
* Epithelial
*Mesenchymal

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4
Q

Process of assessing cytology

A
  1. Is there a significant amount of immune cells?
  2. What tissue cell type is present?
  3. Is there neoplasia present?
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5
Q
  1. Is there a significant amount of immune cells?
A

Neutrophilic (suppurative or acute) inflammation
Includes “abscess”
Pyogranulomatous inflammation
Granulomatous (macrophagic or chronic) inflammation
Eosinophilic inflammation
“Septic” vs “no organisms seen”

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6
Q
  1. What tissue cell type is present?
A

Epithelial?
Round?
Mesenchymal?

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7
Q

Epithelial skin tumours

A

Adherent together
White line between cells
Some order to structure

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8
Q

Epithelial skin tumour examples

A

Trichoblastoma
Basal cell tumour
Trichoepithelioma
Hair follicle tumour
Squamous cell carcinoma
Seen in white cats (UV light)
Sebaceous cell tumours
Adenoma
Carcinoma
Epithelioma
Anal sac apocrine adenocarcinoma
Perianal gland (hepatoid) adenoma

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9
Q

Mesenchymal skin tumours

A
  • Arise from:
    ○ Connective tissue
    ○ Muscle
    ○ Bone & cartilage
    ○ Nerve cells
    ○ Endothelial cells
  • Cells in non-cohesive aggregates or individually
  • Cell borders are variably defined and often indistinct
  • Embedded in matrix
  • Spindle shaped cells with cytoplasmic tails common
  • Cells can be oval or plump
  • Often won’t make definitive characterisation of mesenchymal proliferation by cytology
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10
Q

Mesenchymal skin tumour examples

A

Fibroma and fibrosarcoma
Lipoma and liposarcoma
Perivascular wall tumours
Haemangiopericytoma
Myopericytoma
Anaplastic sarcoma with giant cells
(malignant fibrous histiocytoma)
Haemangioma/haemangiosarcoma
Peripheral nerve sheath tumour
Myxoma/myxosarcoma
Melanoma
Granulation/healing

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11
Q

Lipoma

A
  • Adipocytes with small nucleus and abundant cytoplasm
    ○ Same size nucleus just less magnification needed to view cell
  • Free fatty droplets
  • Cells may fall off slides during staining/fixation
    ○ Avoid methanol fixation
    ○ Consider drop rather than drip
  • Subcutaneous fat appears identical to lipomas
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12
Q

Round cell tumours

A

Individual cells
Round/roundish
High cell harvest
Look at nucleus:
○ Cytoplasmic ratio
Look at position of nucleus to determine cell type
Look in cytoplasm

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13
Q

Round cell tumour examples

A

Mast cell tumour
Lymphoma
Plasmacytoma
Histiocytic tumours
Transmissible venereal tumours (TVT)

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14
Q

Plasmacytoma

A

Discrete cells
More eccentric nuclei - pushed up against walls
Chromatin clumping
Perinuclear clear zones - pale areas near nucleus

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15
Q
  1. Is there neoplasia present
A

Are there cells present that shouldn’t be in this tissue?
Is it benign or malignant?

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16
Q

Benign Mass cytology

A

Minimal - mild anisocytosis
Normal - reduced nuclear:cytoplasmic ratio
Minimal - mild anisokaryosis
Low mitotic count

17
Q

Malignant Mass cytology

A

Marked anisocytosis
Increased nuclear:cytoplasmic ratio
Marked anisokaryosis with frequent binucelation
High mitotic count