Abbas Agaimy, MD Erlangen, Germany The 10th Arkadi M. Rywlin International Pathology Slide Seminar Symposium in Anatomic Pathology, May 21 – 23, 2018 Split, Croatia CASE #34 Abbas Agaimy, MD Erlangen, Germany abbas.agaimy@uk-erlangen.de

Objectives of this case Recognize a distinctive tumor type (birth of a new entity!). Appreciate its association with a hereditary disease.

AMR Case #34 Caucasian male. Multiple lipomas excised at age 26 y. (Neck, trunk & upper arm). Then again at age 34 from similar sites. At age 35: bilateral scrotal masses (submited slides). No other special history submitted.

Bilateral scrotal tumors (courtesy of Dr. W. Schaschkow, Gelsenkirchen, Germany)

At low power, well circumscribed with striking size variation of adipocytes

Striking fat cell size variation (anisocytosis) but little atypia

Degenerative changes (variable staining of cell borders

Grape-like atypical vacuolation S100

Chicken-wire phenomenon of cell borders/periphery

Mild atypia & vacuolated nuclei (Lochkerne)

Mild atypia & vacuolated nuclei (Lochkerne) are typical

Ruptured single fat cells with histiocytes encasing them

Rb1 lost in most of fatty & stromal cells

Other markers tested CD34: pos in scattered stromal cells MDM2&CDK4 IHC: neg MDM2&CDK4 FISH: neg for amplification Rb1 FISH: no abnormality detected in this tumor

What is your diagnosis?

Our case ordinary lipoma

Our case conventional ALT

Our case pleomorphic/SCL

What is your diagnosis? Not an ordinary lipoma. Not a conventional ALT. No classical spindle cell lipoma component. ????

USCAP 2015 (Boston)

On the occasion of his scrotal lipomas, it came out that this patient had a retinoblastoma at age 1.

Male. Multiple lipomas excised at age 26 y. (Neck, trunk & upper arm). Then again at age 34 from similar sites. At age 35: bilateral scrotal masses (submited slides). Striking concordance between the two cases

M: F = 7:1 Age 22-87 (M: 51 y) Site: mainly upper back, shoulders or posterior neck 15% multiple (2 to 5 tumors) Rb1 loss by ICH: 69% cases. >23% Rb1 deletions by FISH Local rec: 16%.

TP53

Take-home-message Dysplastic (anisometric cell) lipoma is a frequent but likely misnamed subcutaneous fatty neoplasm. Distinctive from conventional ALT histolgically and by IHC. Distinctive from conventional pleomorphic/spindle cell lipoma. Has a recurrence rate in the range of 16%. No dedifferentiation reported. Tends to be frequently multifocal. Associated with childhood retinoblastoma in a subset of cases.

29 Kilometer apart City of Berber Sudan

Thank you for your attention 29 Kilometer apart City of Atbara Kamal G. Ishak (1932-2004) City of Berber Sudan