3rd Pannonia Congress of Pathology, Bled 2014Slide Seminar UROPATHOLOGY

CASE 7

Metka VolavšekInstitute of Pathology, Faculty of MedicineLJUBLJANA, SLOVENIA

CASE HISTORY

• 18 year old male patient

• enlargement of the right hemiscrotum of unknownduration

• ultrasound epididymal tumor

• Th: excision

MACROSCOPY

• surgical specimen (slide case 7)

• weight 118 g• largest diameters: 7 x 6 x 5 cm• outer surface: smooth, glistening, partially fibrosed• cut surface:

• overgrown with tumor• yellow-white, soft and partially cystic• only partial preservation of epidydymal structure

HISTOLOGY

• Tumor:• highly cellular• cells round/ovoid, some spindle shaped

• cytoplasm- scarce or moderately abundant• nuclei - pleomorphic, partially segmented• nucleoli - prominent• high mitotic activity• atypical mitoses

Ki-67desmin

desmin

PTAH

Myf-4

Case 7 DIAGNOSIS

• Embryonal rhabdomyosarcoma, anaplastictype (with diffuse anaplasia)

• MR imaging of pelvic and scrotal area-neg.Stage T2N0M0 (epididymis + focal infiltration of spermatic cord)

• Tumor focally close the resection margins(mesenchymal council) orchidectomy (1 mthafter 1st excision) +CT +RT

• MI: fibrous scar with foreign body granulomas; noresidual tumor

THERAPY AND FOLLOW UP

FOLLOW UP

• TH with complete response:• supplementary chemotherapy started 3 mths after 1st resection

(VAIA), bone marrow supression-dose to 75%• irradiation of paraaortal and R iliacal region

• linear accelerator with photones in fractions of 180 cGy• irradiation with electrons-postoperative field :

• scrotal region (total dose 40Gy) and• R inguinal area- (total dose 30 Gy)

• complete remission-6 months after 1st resection

• follow up: more than 7 years• the patient is well, without any signs of disease

RHABDOMYOSARCOMA

• DEF: Rhabdomyosarcoma (RMS) - the most common soft-tissue sarcoma of childhood and adolescence,usually before age 20

• LOC: any anatomic locationmost in the head and neck or genitourinary tract (where there is little if any skeletal muscle as anormal constituent)in the extremities - appear in relation to skeletal muscle

• MORPH: RMS is histologically subclassified into embryonal, alveolar, pleomorphic, and sclerosingvariant

• the diagnostic cell in all types of RMS—rhabdomyoblast• eccentric eosinophilic granular cytoplasm rich in thick and thin filaments• may be round or elongate (known as tadpole or strap cells), may contain cross-striations• EM- rhabdomyoblasts contain sarcomeres, and IHC- antibodies to the myogenic markers desmin,

MYOD1, and myogenin

• RMS aggressive neoplasms TH: usually treated with surgery and CT, +/- RT

• Survival: influenced by histologic type and location of the tumor

• BOTRYOID SUBTYPE HAS THE BEST PROGNOSIS

• anaplastic embryonal, pleomorphic, and alveolar variants - often fatal

RHABDOMYOSARCOMA-genitourinary tractPARATESTICULAR RHABDOMYOSARCOMA

• LOC: may arise in the testicular tunics, epididymis, or spermatic cord• large / locally invasive tumor - exact site of origin cannot be determined

• Rhabdomyosa- most common sa of paratesticular area in children; peak incidence at 9 ys• MA:

• encapsulated white-gray mass with focal hemorrhage and cystic degeneration• up to 20 cm in diameter

• MI: most paratesticular- embryonal rhabdomyosa (alveolar, botryoid, pleomorphic rarely observed)• myxoid spindle cell tumor with cellular and less cellular areas or interlacing fascicles of spindle cells

• small round or spindle cells with dark nuclei• scant dense eosinophilic cytoplasm (rhabdomyoblasts)• variable numbers of cells showing cross striation• connective tissue stroma may be myxoid

• SPREAD: usually to retroperitoneal LN orchiectomy and RPLNDloc invas rhabdomyosa (skin inv + clin susp inguinal LN) orchiectomy, scrotectomy + inguinal LND

• Long-term survival rates in patients receiving adjuvant RT and combination CT >80%• Anaplastic cellular features: in 13% of all subtypes of rhabdomyosa• Anaplasia (def): neoplastic nuclei at least 3 x the size of their neoplastic neighbors and/or atyp mit figures

• Focal: anaplastic cells loosely scattered among non-anaplastic tumor cells• Diffuse: anaplastic cells arranged in multiple clusters or diffuse sheets

EMBRYONAL RHABDOMYOSARCOMA (ER)• DEF: Primitive myoblastic neoplasm most commonly found in hollow visceral organs, genitourinary tract and head/neck region• Most common type of rhabdomyosarcoma (68%); Population: 42% children < 4 years of age, may be seen in adults• Considered a favorable histologic type, 5-year failure free survival rate: 82%• MI: alternating cellular and myxoid areas, foci of immature cartilage or bone occasionally present

predominant histologically undifferentiated, hyperchromatic, small cell population (round or spindled)immature cells showing muscle differentiation frequently scattered, rarely predominate

• Round cells with abundant, usually eccentric eosinophilic cytoplasm• Cross striations not typically present• Nuclei frequently vesicular with prominent nucleolus

• Spindle cell myoblasts with prominent tapered fibrillar eosinophilic cytoplasm• May form tadpole or strap cells• Nuclei may be multiple• Cross striations may be present

• presence of anaplasia confers worse prognosis, especially when diffuseThree histologic subtypes of ER1. Not otherwise specified (NOS) - most common2. Botryoid

• Requires by the presence of a condensed layer of neoplastic cells beneath intact epithelium (cambium layer)• Typically separated from mucosa by a myxoid, hypocellular zone• Primarily occurs in mucosal lined sites• Grape like gross appearance is typical but not required

3. Spindled• Spindled morphology• Primarily found in the paratesticular and orbital regions

• No PAX-FOXO1 translocations

Embryonal(botryoid)rhabdomyosarcoma

cambiumlayer

desmin

desmin

ALVEOLAR RHABDOMYOSARCOMA

• DEF: Primitive myoblastic neoplasm, most commonly in the extremities, trunk, paranasal sinuses and parameningeal region• 2nd most common type of rhabdomyosarcoma, comprises 31% of RMS• Population: most >10 years of age, May be seen in adults• Considered an unfavorable histologic type - 5-year failure free survival rate: 65%• MI: sheets of uniform cells, frequently discohesive, broken up by fibrous septae

Generally round to oval nuclei, hyperchromatic with small nucleoliOccasional rhabdomyoblasts seen in 30% of cases (usually round, with fibrillar cytoplasm, cross striations rare)Sheets broken up by fibrous septae (containing vessels)

• Two histologic subtypes:• Classical

• Nests of neoplastic cells arranged in alveolar spaces; Cells adhere to the periphery of the alveoli• Hobnail or tombstone appearance; May look like a non-cohesive papillary pattern• Non-cohesive cells appear to float in the center; Multinucleated giant cell forms may be seen• Nuclei usually peripheral, wreath-like; Normal muscle fibers may be entrapped

• Solid• Sheets of neoplastic cells; Nests separated by thin fibrovascular septae but alveoli are not seen

• PAX-FOXO1 translocations aid in diagnosis and determination of prognosis - Considered diagnostic if present• PAX3-FOXO1 t(2;13)(q35;q14) – 60%; PAX7-FOXO1 t(1;13)(p36;q14) – 20% (better prognosis); Fusion negative ~ 15%

• Anaplastic cellular features may be seen in approximately 13% of all subtypes of rhabdomyosarcoma.• Anaplasia, especially diffuse, carries worse prognosis

Alveolarrhabdomyosarcoma

desmin

Myf-4

PLEOMORPHIC RHABDOMYOSARCOMA

• DEF Malignant neoplasm with large pleomorphic cells exhibiting skeletal muscle differentiation

• Most often seen in adults (rare cases reported in children)• Common sites of involvement:

Deep, extremitiesRetroperitoneum

• Unfavorable histologic type, 5-year failure free survival rate: ~ 40%• MI:

Markedly enlarged pleomorphic cells, abundant deeply eosinophilic cytoplasmCross striations rareMultinucleated forms may be seenSpindled to epithelioid neoplastic cells admixedLacks background of uniform immature cells

• Anaplasia can be very difficult to assess in pleomorphic subtype, carries worse prognosis as in other types• No distinct translocation

SCLEROSING RHABDOMYOSARCOMA

• DEF: Rhabdomyosarcoma with a densely sclerotic background stroma(previously called Sclerosing, pseudovascular rhabdomyosarcoma in adults)

• Rare, <1% of rhabdomyosarcoma , reported in children and adults of all ages

• MI: neoplastic cells set arranged in nests, microalveoli or cords, may produce a pseudovascular patterncomposed of small undifferentiated cellsgiant cells or myoblasts - raredensely hyalinized eosinophilic background stroma

• presence of anaplasia worse prognosis , especially when anaplasia diffuse• No distinct translocation

• Common sites of involvement: extremities, trunk, retroperitoneum , head and neck (in adults)

• Unknown behavior (1 case in the parotid gland* - slow local progression!)

*Lamovec J, Volavšek M. Ann Diagn Pathol 2009; 13: 334–338.

Sclerosingrhabdomyosarcoma

differentiated rhabdomyoblasts were not present.

MyoD1

EMBRYONAL RHABDOMYOSARCOMADIFFERENTIAL DIAGNOSIS

SMALL, BLUE ROUND CELL TUMORS:• Ewing sarcoma/primitive neuroectodermal tumor (PNET)

more uniformly round cell proliferationwithout clear-cut spindle cells and cells with eccentric eosinophilic cytoplasm.a classic Ewing sarcoma/PNET should always express CD99 and is desmin/myogenin/MyoD1 negative.has a characteristic t(11;22)(q12;q24).

• Neuroblastomacharacterized by hyperchromatic nuclei with granular chromatinfine, fibrillar stromapseudorosettes may be presentchromogranin/synaptophysin/neurofilament expression – usually positivemyogenic markers negative

• Nephroblastomamay show skeletal muscle differentiation, but also hasblastema and epithelial differentiation

• Desmoplastic, small, round cell tumoroften contains desmin-positive cells, but has adesmoplastic stromastrong expression of epithelial markerstypical t(11;22)(p13;q12)

EMBRYONAL RHABDOMYOSARCOMADIFFERENTIAL DIAGNOSIS cont‘d

• small-cell synovial sarcomashould express epithelial markersno myogenic markersIs characterized by t(X;18)(p11.2;q11.2).

• non-Hodgkin’s lymphomaCD45 and B- or T-cell markers

• malignant rhabdoid tumoralso shows eccentric cytoplasm, butnuclei are more vesicular with prominent nucleolirhabdoid cells should be cytokeratin positive

• rhabdomyoma …

• solid variant of alveolar rhabdomyosarcoma…

older adults• history of well-diff. liposarcoma (atypical lipomatous tumor)• retroperit. or spermatic cord > extremity, subcutaneous rare

MA: large firm mass (“fish-flesh”), coarse lobulationoften surr. by benign appearing well diff. component

MI:• areas of atypical lipomatous component• well diff. and dediff. components, often with abrupt

transition

Dedifferentiated component :• cellular, nonlipogenic sarcoma with 5+ mitotic figures/10 HPF• high grade, often resembles MFH (fascicles of spind+pleom c)•

Metastases: usually only dediff component

IHC: MDM2+, CDK4 +(both together are sensitive and specific),• Also +: vim, p53, Rb (66%), PPAR-gamma, foc + for SMA

FISH: MDM2+

• 12q14 amplification- supernumerary ring chromosomes derivedfrom 12q(13-15)genetic analysis (same findings as atypical lipomatous tumor)

DedifferentiatedLiposarcoma

vim

MDM2

Malignant Rhabdoid Tumor

• Children: < 5 ys, >80% < 2 ys, median age-1 year• 2% to 3% of malignant renal tumors in children• unicentric, unilateral, poorly delineated

• LOC: kidney, brain (mostly in the midline cerebellum), reported inpractically every location in the body, including the brain, liver, softtissues, lung, skin, and heart.

• MI: cells resemble rhabdomyoblasts, no muscle differentiationmonot sheets, loosely cohesive c, dist cell borderscells are large, polygonalnuclei vesic single cherry-red nucleolijuxtanuclear, glob, eosin cytopl incl (whorled interm fil)

• aggress infiltr of adjacent renal parenchyma + ext VI common

• Molec/ cytogenetics: biallelic inactivation of hSNF5/INI1 TSGlocated on chrom 22q

• Cca 15-20 % of patients with MRT of the kidney synchr ormetachr CNS lesions (metastases and/or second prim cancers)(medulloblastoma, PNET, or atypical teratoid-rhabdoid tumor)

Figs. Medscape; Immuno.med.cobe

Figs. Webpathology.com

Desmoplastic SmallRound Cell Tumor

Children, young adults (adolescent boys)MA: Large mass (abdomen, pelvis) accompanied bywidespread peritoneal tumor implantsOther loc: pleura, thorax, scrotum, CNS

MI: Solid nests of round/oval cells surrounded by cellulardesmoplastic stromaAlso: necrosis, cystic degeneration, glandular arrangements,signet ring-like cells, pseudorosette formations, rhabdoidcells, extensive areas of predominantly spindle cellmorphology, carcinoid-like differentiation, adenoid cystic-likeconfiguration

IHC: divergent phenotype, epithelial myogenic markers, mostsensitive: desmin and CAM 5.2.WT1 (C-19) (also + in nephroblastomas)

Molec/ cytogenetics: detection of the EWS-WT1 gene fusionis characteristic of desmoplastic small round cell tumor(reliable use in tumor diagnosis)t(11;22)(p13;q11.2 or q12): WT1-EWS , alsot(21;22)(q22;q12): ERG-EWS

Nephroblastoma-Wilmstumor

DEF: Malignant embryonal neoplasm derived from nephrogenicblastema cells; 85% of ped. renal mal.

Peak incidence: 2-3 ys; 98% cases-children < 10 ysOverall survival currently > 90%

Unfavorable: high stage at presentationdiffuse anaplasia (unfavorable histology)

Presentation: abdominal mass, pain, hematuria, hypertension,acute abdominal crisisMI: Most characteristic - Triphasic pattern

undifferentiated blastema epithelial stromal components

(may be biphasic or rarely monophasic)

Features of anaplasia include markedly increased (3x) tumorcell nuclei with hyperchromasia and multipolar mitotic figuresOnly diffuse anaplasia clinically/therapeutically important differentiation from focal anaplasia essential

IHK: WT1 protein (+ blastemal and epithelial elements; stroma -)Blastemal cells: desmin+, other – (actin, myogenin, MYOD1)Vim CK – or foc+ (blastema); CK+ epithelial componentspax-2 +Molec/cytogenetics: cca 10% assoc. with syndromic conditionsWT1 Gene (chrom 11p13) deletions or point mutations

Medulloblastoma(with myogenic differentiation)

MRQ-40 Sy38

SMI32 SMI31

desminGFAPFigs. provided by prof. Mara Popović

Ewing sarcoma family (Ewing sarcoma and PNET):

Small round cell neoplasm of bone and soft tissue

spectrum of appearance undifferentiated rosetteforming (derived from neural crests cells)

• with neural differentiation PNETs• undifferentiated Ewing sarcoma

Both: similar neural phenotype, share identical chrom.translocation two variants of the same tumor (differingin degree of neural differentiation); distinction of no clinsignificance

Together cca 6% - 10% of primary malignant bone tumors2nd most common bone sarcomas in childrenPeak incidence 10 to 15 years age, cca 80% < 20 years

M>F (slightly); striking predilection for whites

MI: rosettes with a neurofibrillar center (Homer-Wrightrosettes); cytoplasm scanty, pale stained, often vacuolated(glycogenPAS+)

IHC: CD99 + (>90%), NSE, Sy, Chrom, CD57

Molec/cytogenetics: five characteristic chromosomaltranslocations involving the EWS gene

>90% t(11;22)(q24;q12); <5% cases- no translocation

Ewing Sarcoma/PrimitiveNeuroectodermal Tumor (PNET)

CD99

NHL:

ALCLCD30

DLBL

CD20

FCC

Bcl-6Precursor Bcell-ALL

CD10

B-SLL/CLL

CD23

CONCLUSIONS

• rhabdomyosarcoma tumor of children+young adults (<20ys)

• paratesticular RSA usually of embryonal type (consideredprognostically favourable)

• anaplasia (diffuse) worse prognosis

• wide differential diagnosis (use of IHC, molecular/geneticstudies)

acknowledgements

• B Grčar Kuzmanov

• J Lamovec

• M Popović

• M Velikonja

• M Živanović