Adenosquamous carcinoma may be considered a variant of metaplastic carcinoma
It should be diagnosed separately because of its distinct histologic appearance and its low grade behavior
Metaplastic carcinoma includes pure squamous carcinoma and usual infiltrating carcinoma with squamous metaplasia plus those with mesenchymal metaplasia
Same age range as usual infiltrative carcinoma (33-88 years)
Low grade, but malignant, behavior
1/12 with axillary dissection had a single positive node
Of 25 patients with at least one year followup
5 with local recurrence
One progressed to death
All metastases to nodes or distant sites in patients <40 years of age and >3 cm diameter primary
Grading / Staging / Report
Grading
Adenosquamous carcinoma is by definition low grade
Bloom-Scarff-Richardson grading scheme is most widely used
Total score and each of the three components should be reported
Based on invasive area only
Tubule formation
Score
>75% tubules
1
10-75% tubules
2
<10% tubules
3
Nuclear pleomorphism (most anaplastic area)
Score
Small, regular, uniform nuclei, uniform chromatin
1
Moderate varibility in size and shape, vesicular, with visible nucleoli
2
Marked variation, vesicular, often with multiple nucleoli
3
Mitotic figure count per 10 40x fields (depends on area of field, see key below)
Score
0.096 mm2
0.12 mm2
0.16 mm2
0.27 mm2
0.31 mm2
0-3
0-4
0-5
0-9
0-11
1
4-7
5-8
6-10
10-19
12-22
2
>7
>8
>10
>19
>22
3
Olympus BX50, BX40 or BH2 or AO or Nikon with 15x eyepiece: 0.096 mm2
AO with 10x eyepiece: 0.12 mm2
Nikon or Olympus with 10x eyepiece: 0.16 mm2
Leitz Ortholux: 0.27 mm2
Leitz Diaplan: 0.31 mm2
Mitotic count figures based on original data presented for Leitz Ortholux by Elston and Ellis 1991, with modifications based on pubished and measured areas of view
Evaluate regions of most active growth, usually in cellular areas at periphery
We employ strict criteria for identification of mitotic figures
Sum of above three components
Overall grade
3-5 points
Grade I (well differentiated)
6-7 points
Grade II (moderately differentiated)
8-9 points
Grade III (poorly differentiated)
Staging
TNM staging is the most widely used scheme for breast carcinomas but is not universally employed
Critical staging criteria for regional lymph nodes
Isolated tumor cell clusters
Usually identified by immunohistochemistry
Term also applies if cells identified by close examination of H&E stain
No cluster may be greater than 0.2 mm
Multiple such clusters may be present in the same or other nodes
Micrometastasis
Greater than 0.2 mm, none greater than 2.0 mm
Metastasis
At least one carcinoma focus over 2.0 mm
If one node qualifies as >2.0 mm, count all other nodes even with smaller foci as involved
Critical numbers of involved nodes: 1-3, 4-9 and 10 and over
Note extranodal extension
Report
Excisions: the following are important elements that must be addressed in the report for infiltrative breast carcinomas
Grade
Total score and individual components
Size of neoplasm
Give 3 dimensions or greatest dimension
Critical cutoffs occur at 0.5 cm and at 2 cm
Margins of resection
Measure and report the actual distance of both invasive and in situ carcinoma
Angiolymphatic invasion
Indicate if confined to tumor mass, outside tumor mass or in dermis
(Extensive DCIS is not currently felt to be a significant predictor of behavior)
Results of special studies performed for diagnosis
Results of prognostic special studies performed
ER, PR, Proliferation marker, Her2neu
If studies were performed on a prior specimen, refer to that report and give results
Needle or core biopsies
Provisional grade may be given but may defer to excision for definitive grade
Presence of absence of angiolymphatic invasion
Results of special studies performed for diagnosis
Results of prognostic special studies if performed
ER, PR, Proliferation marker, Her2neu
State if studies are deferred for a later excision specimen
Elston CW, Ellis IO. Pathological prognostic factors in breast cancer. I. The value of histological grade in breast cancer: experience from a large study with long-term follow-up. Histopathology. 1991 Nov;19(5):403-10.
Rosen PP, Ernsberger D. Low-grade adenosquamous carcinoma. A variant of metaplastic mammary carcinoma. Am J Surg Pathol. 1987 May;11(5):351-8.
Drudis T, Arroyo C, Van Hoeven K, Cordon-Cardo C, Rosen PP. The pathology of low-grade adenosquamous carcinoma of the breast. An immunohistochemical study. Pathol Annu. 1994;29 ( Pt 2):181-97.
Van Hoeven KH, Drudis T, Cranor ML, Erlandson RA, Rosen PP. Low-grade adenosquamous carcinoma of the breast. A clinocopathologic study of 32 cases with ultrastructural analysis. Am J Surg Pathol. 1993 Mar;17(3):248-58.
Suster S, Moran CA, Hurt MA. Syringomatous squamous tumors of the breast. Cancer. 1991 May 1;67(9):2350-5.
Foschini MP, Pizzicannella G, Peterse JL, Eusebi V. Adenomyoepithelioma of the breast associated with low-grade adenosquamous and sarcomatoid carcinomas. Virchows Arch. 1995;427(3):243-50.
Ferrara G, Nappi O, Wick MR. Fine-needle aspiration cytology and immunohistology of low-grade adenosquamous carcinoma of the breast. Diagn Cytopathol. 1999 Jan;20(1):13-8.
Kawaguchi K, Shin SJ. Immunohistochemical staining characteristics of low-grade adenosquamous carcinoma of the breast. Am J Surg Pathol. 2012 Jul;36(7):1009-20
