TUMORS AND TUMOR-LIKE LESIONS

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CHAPTER 6 TUMORS AND TUMOR-LIKE LESIONS

Pediatric ‘blastomas’ / ‘small round cell’ tumors

Introduction
Handling of pediatric tumor specimens
Peripheral neuroblastic tumors (NTS)
Neuroblastoma
Ganglioneuroblastoma, intermixed
Ganglioneuroblastoma, nodular
Ganglioneuroma
Neuroblastic tumor, unclassifiable
Neuroblastoma (schwannian stroma poor), nos
Rhabdomyosarcoma
Embryonal rhabdomyosarcoma
Alveolar rhabdomyosarcoma
Extraskeletal myxoid chondrosarcoma
Desmoplastic small round cell tumor
Extrarenal malignant rhabdoid tumor
Primitive neuroectodermal tumor (PNET)

Lipomatous tumors

Lipoblastoma / lipoblastomatosis
Lipoma
Lipomatosis
Lipomatosis of nerve / fibrolipomatous hamartoma of nerve
Fibrolipomatous hamartoma of calcaneum
Angiolipoma
Hibernoma
Myxoid liposarcoma

Spindle cell tumors

Nodular fasciitis
Proliferative fasciitis / myositis
Myositis ossificans
Myositis ossificans progressiva / fibrodysplasia ossificans progressiva
Fibrous hamartoma of infancy
Myofibromatosis
Fibromatosis colli
Juvenile hyaline fibromatosis
Inclusion body fibromatosis
Fibroma of tendon sheath
Desmoplastic fibroblastoma
Calcifying aponeurotic fibroma
Angiomyofibroblastoma
Superficial fibromatoses
Desmoid-type (aggressive) fibromatosis
Lipofibromatosis
Gardner fibroma
Calcifying fibrous tumor
Solitary fibrous tumor
Inflammatory myofibroblastic tumor
Low grade myofibroblastic sarcoma
Congenital / infantile fibrosarcoma
Adult-type fibrosarcoma
Low grade fibromyxoid sarcoma
Sclerosing epithelioid fibrosarcoma
Angioleiomyoma
Leiomyosarcoma
Smooth muscle tumors in immunocompromised patients
Fetal-type rhabdomyoma

Other pediatric tumors

Soft tissue chondroma
Angiomatoid fibrous histiocytoma
Mixed tumor / myoepithelioma/ parachordoma
Synovial sarcoma
Epithelioid sarcoma
Alveolar soft part sarcoma
Clear cell sarcoma of soft tissue (malignant melanoma of soft parts)
t(15;19) translocation tumors / nut rearrangement carcinomas (NRC) / midline nut carcinomas (MNC)
Giant cell tumor of tendon sheath
Diffuse type giant cell tumor / pigmented villonodular synovitis
Plexiform fibrohistiocytic tumor
Giant cell tumor of soft tissue
Pecomas

Vascular-related tumors

Introduction
Immunohistochemical staining
Glomus tumors
Myopericytoma
Synovial hemangioma
Intramuscular hemangioma
Venous hemangioma
Arteriovenous hemangioma / malformation
Epithelioid hemangioma
Diffuse angiomatosis
Lymphangioma / lymphatic malformation
Kaposiform hemangioendothelioma
Retiform hemangioendothelioma
Papillary intralymphatic angioendothelioma (PILA)
Kaposi sarcoma
Epithelioid hemangioendothelioma
Angiosarcoma
Infantile capillary hemangioma

INTRODUCTION

• Although many tumors are more common at certain sites, for ease of reference, the majority of tumors or lesions which may be resected or biopsied with a clinical suspicion of tumor, are included in this section
• Tumors which only affect a very specific site are included in their respective system chapters
• Most of the lesions covered here would be broadly considered ‘pediatric soft tissue tumors’

PEDIATRIC ‘BLASTOMAS’ / ‘SMALL ROUND CELL’ TUMORS

INTRODUCTION

• A large number of pediatric embryonal tumors share a component with a ‘small round blue cell’ phenotype (SRBCT)
• Many of the diagnostic morphological findings require assessment of overall architecture and other features which may not necessarily be present in needle core biopsy specimens
• Immunohistochemical staining and molecular techniques may be required in a large proportion of such specimens for definitive diagnosis
• A targeted immunohistochemical panel should be performed to determine appropriate positive and negative findings
• Since morphological features may be non-diagnostic, adequate clinical history, imaging and results of other investigations are essential for appropriate interpretation
• Even if a diagnosis is suggested clinically, always review all other possibilities

image pediatric tumors may present in an atypical fashion at atypical sites and the apparent history submitted may be misleading

• The most immediate issues for management in most cases are the differential between leukemia / lymphoma, rhabdomyosarcoma, other high grade embryonal sarcoma such as PNET and other less aggressive tumors
• Due to their rarity, and hence potential diagnostic difficulty, in non-specialist centers, primary diagnosis of all embryonal pediatric tumors should be reviewed by a specialist center / review panel and additional investigations performed as required

HANDLING OF PEDIATRIC TUMOR SPECIMENS

• Many pediatric tumors require additional investigations for their definitive diagnosis and prognosis

image immunostaining
image molecular investigation
image electron microscopy

• Optimal specimen handling makes performance and interpretation of these techniques much easier
• All diagnostic pediatric tumor specimens should be submitted to the laboratory as fresh tissue immediately following biopsy where possible
• The specimen should be divided according to predetermined standard operating procedures, with aliquots for:

image formalin fixation and paraffin embedding
image glutaraldehyde fixation for electron microscopy
image snap freezing or storage in RNA protection medium for molecular studies such at RT-PCR
image imprints / ‘dabs’ fixed for FISH in methanol
image sample for cytogenetic studies
image frozen for storage and subsequent analysis if required

• All laboratories providing a diagnostic pathology service for pediatric tumors should have facilities available for handling of fresh specimens and access to appropriate molecular diagnostic services
• Advances in technical aspects now mean that many molecular techniques, such as FISH and RT-PCR, may also be performed on routinely fixed paraffin embedded material

image this should be carried out by centers experienced in their interpretation since the diagnostic yield is lower and technical aspects of the test performance and interpretation may require modification

Issues specific to needle core biopsy specimen interpretation in pediatric tumor diagnosis (Figs 6.1, 6.2)

• In an increasing number of centers, primary diagnostic investigation of suspected pediatric tumors is on the basis of an image guided needle core biopsy
• Limited amounts of tissue are obtained, making optimal specimen handling of importance
• A full range of ancillary investigations is possible in the vast majority of needle biopsy specimens in centers experienced in their handling
• Limited material is available for morphological analysis in such cases

image many of the ‘diagnostic’ architectural features referred to in standard texts may not be applicable to the interpretation of these limited samples
image extensive use of ancillary investigations such as immunostaining and molecular analysis should be carried out where required in order to reach a definitive diagnosis

• ‘Molecular profiling’ of tumors is likely to become of increasing importance for both determining diagnosis, and prognosis and management in pediatric tumors

image traditional morphological characteristics may become less applicable due to changes in understanding of the biology of these tumors

• Needle biopsies are safe, with a high adequacy rate and diagnostic yield and associated low morbidity

image both complication rate and adequacy are operator dependant

– ideally performed in specialist centers

• The report in such cases should provide as much information as possible, but not more

image caution not to overinterpret non-diagnostic findings in limited samples

image

Fig 6.1 Low power scan of a glass slide with tumor core biopsies demonstrating multiple cores of tissue for diagnosis.

image

Fig 6.2 Low power photomicrograph of a tumor core biopsy demonstrating adequate material for diagnosis.

PERIPHERAL NEUROBLASTIC TUMORS (NTS)

• Classified on the basis of the histological features into four main types [International Neuroblastoma Pathology Classification (INPC) system; Shimada et al 1999]:

image Neuroblastoma

– NB; Schwannian stroma-poor

image Ganglioneuroblastoma, intermixed

– GNBi; Schwannian stroma-rich

image Ganglioneuroblastoma, nodular

– GNBn; composite Schwannian stroma-rich/stroma-dominant and stroma-poor

image Ganglioneuroma

– GN; Schwannian stroma-dominant

image NT – unclassifiable
• Overall around 85% are NB, 5% GNBi, <1% GN and 5–10% GNBn (Shimada et al 2003)
• May occur at wide range of sites

image most commonly adrenal glands and retroperitoneal primary sites

– thoracic NTs relatively more likely to represent GNB, GN

image can present with metastatic disease

• Risk stratification for prognosis and management is based on age, stage, MYCN, and Shimada pathology classification, and an increasing number of other molecular (biological) markers

NEUROBLASTOMA

• Incidence around 1 per 100,000 (Schwab et al 2003)
• 70% have metastatic disease at presentation (Ara et al 2006)
• Age, clinical stage, molecular findings and undifferentiated subtype influence overall survival (Lastowska et al 2002, Shimada et al 2001, Goto et al 2001, Ikeda et al 2002, Burgues et al 2006, Navarro et al 2006, Sano et al 2006)

Histopathological features (Figs 6.3–6.8)

• International Neuroblastoma Pathology Classification (INPC) system (Shimada et al 1999)
• By definition

image Schwannian stroma comprises <50% of the tumor

• Sheets or nests of neuroblasts

image varying stages of differentiation
image background neurofibrillary stroma
image variegated (‘salt and pepper’) chromatin pattern

image

Fig. 6.3

image

Figs 6.3–6.4 Macroscopic photographs of adrenal-associated neuroblastomas, demonstrating variable appearance from expansion of the adrenal cortex by dark tumor to nodular architecture of soft, cream-brown viable tumor.

image

Fig. 6.5

image

Fig. 6.6

image

Fig. 6.7

image

Figs 6.5–6.8 Photomicrographs of cases of neuroblastoma, demonstrating tumor composed of sheets and nests of small ovoid cells within a variably prominent neurofibrillary background.

NB, undifferentiated

• No obvious morphological differentiation

image no ganglion cell differentiation of neuroblasts
image no definite neurofibrillary stroma on light microscopy
image sheets of small round to ovoid cells

• Supplementary techniques such as immunohistochemical staining and biological marker status required for the definitive diagnosis

NB, poorly differentiated

• Morphological nests of neuroblasts

image within neurofibrillary background stroma

– usually identifiable on routine light microscopy

• <5% of neuroblasts show ganglion cell differentiation

NB, differentiating

• Morphological nests of neuroblasts

image within neurofibrillary background stroma

– usually identifiable on routine light microscopy

• >5% of neuroblasts show ganglion cell differentiation

image synchronous maturation of both:

– nucleus

· eccentric position
· loss of ‘salt and pepper’ chromatin pattern
· prominent nucleolus

– cytoplasm

· abundant eosinophilic / amphophilic

image cell diameter more than twice nuclear diameter

Immunohistochemical staining (Figs 6.9, 6.10)

• CD56+

image also highlights neurofibrillary stroma

• NB84+
• CD44+

image associated with better prognosis

– but also correlated with other INPC features (Munchar et al 2003)

• Schwannian stroma is S100+
image

Fig. 6.9

image

Figs 6.9–6.10 Photomicrographs of cases of neuroblastoma, immunostained to demonstrate strong and uniform expression of CD56 (NCAM) by both tumor cells and neurofibrillary stroma, and cytoplasmic granular expression of NB84.

GANGLIONEUROBLASTOMA, INTERMIXED (Figs 6.11–6.14)

• Well defined nests of neuroblasts

image within neurofibrillary background stroma

– intermixed / scattered throughout the lesion

image usually differentiating neuroblasts within the nests

• No discreet macroscopically identifiable nodule
• <50% of the lesion represented by NB
• >50% of the lesion represented by Schwannian stroma and mature ganglion cells
image

Fig. 6.11

image

Figs 6.11–6.12 Macroscopic photographs of ganglioneuroblastoma, intermixed, demonstrating solid expansile masses with yellow cut surface. Note the area of hemorrhage in Fig 6.12 compared to the area of neuroblastomatous tissue in ganglioneuroblastoma, nodular in Fig 6.15.

image

Fig. 6.13

image

Figs 6.13–6.14 Photomicrographs of cases of ganglioneuroblastoma, intermixed, in which, overall, >50% of the lesion is represented by Schwannian stroma and mature ganglion cells, with admixed well-defined nests of neurofibrillary stroma, within which are differentiating neuroblasta.

GANGLIONEUROBLASTOMA, NODULAR (Figs 6.15–6.17)

• Macroscopic, hemorrhagic nodule within a larger bland lesion
• Surrounding areas of stroma-rich or stroma-dominant areas with mature or maturing ganglion cells
• Well demarcated nodule of Schwannian stroma-poor neuroblastomatous tissue

image may be multiple
image nodules morphologically those of neuroblastoma (see above)

• Outcome of GNBn

image based on prognostic features of the NB component (Peuchmaur et al 2003)

– including all molecular / biological markers

image

Fig 6.15 Macroscopic photograph of a ganglioneuroblastoma, nodular demonstrating a uniform, bland solid yellow lesion with a macroscopically visible area of hemorrhagic neuroblastoma.

image

Fig. 6.16

image

Figs 6.16–6.17 Photomicrographs of a ganglioneuroblastoma, nodular in which most areas are composed of Schwannian stroma and mature ganglion cells, but the hemorrhagic nodule shows features indistinguishable from neuroblastoma.

GANGLIONEUROMA (Figs 6.18–6.20)

Ganglioneuroma, maturing

• Predominant Schwannian stroma
• Scattered collections of mature and maturing ganglion cells
• No distinct nests of neuroblasts / maturing ganglion cells

image cf GNBi

• No nests containing neuropil
image

Fig 6.18 Macroscopic photograph of a ganglioneuroma, demonstrating a solid bland lesion with a uniform cut-surface.

image

Fig. 6.19

image

Figs 6.19–6.20 Photomicrographs of a ganglioneuroma, demonstrating the entire lesion to be composed of predominant Schwannian stroma with loose collections of mature and maturing ganglion cells but no true nests containing neurofibrillary material.

Ganglioneuroma, mature

• Entire lesion composed of mature Schwannian stroma and ganglion cells only

NEUROBLASTIC TUMOR, UNCLASSIFIABLE

• May be used in small biopsy specimens since representativeness is unknown

NEUROBLASTOMA (SCHWANNIAN STROMA POOR), NOS

• Definite NB but subtyping not possible due to necrosis, etc

Additional investigations

• Molecular studies are mandatory in risk stratification and management planning in neuroblastic tumors

image importance of optimal specimen handling to allow FISH and other molecular studies

• Current biological markers associated with adverse prognosis (Lastowska et al 2001, Schwab et al 2003) (Figs 6.21–6.23):

image MYCN amplification
image DNA diploidy
image 1p deletion
image 17q gain
• Mitosis karyorrhexis index (MKI)

image calculated per 5000 neuroblasts

– usually 6–8 hpf in cellular tumors

· must be 3 µm thick and evenly stained

image classified as:

– low <2%
– intermediate 2–4%
– high >4%

image high MKI is also associated with MYCN amplification
image MKI not carried out on small needle biopsy specimens or post-treatment specimens

image

Fig. 6.21

image

Fig. 6.22

image

Figs 6.21–6.23 FISH studies on imprint preparations from neuroblastomas, demonstrating MYCN amplification, 1p loss and 17q gain respectively.

Pitfalls and specific issues

• NT, unclassifiable may be used in small needle biopsy specimens

image in this setting biological markers become of increasing importance

• Do not diagnose as GN on a small needle biopsy

image may be GNBn

• If diagnosing tumor type from metastatic site, state this clearly on the report
• The morphological classification is based on surgical resections of pre-treatment specimens

image these are almost never encountered now in the UK since initial biopsies are needle core biopsies for diagnosis
image post-treatment specimens should be reported as post-treatment NTs with a description of the elements present (Figs 6.24, 6.25)

– classification above is not applicable

• MYCN status remains valid even on viable post-treatment samples
image

Fig 6.24 Macroscopic photograph of a post-chemotherapy neuroblastoma, demonstrating areas of hemorrhage, necrosis and dystrophic calcification.

image

Fig 6.25 Photomicrograph of a post-chemotherapy neuroblastoma, demonstrating changes of calcification, collections of hemosiderin-laden and foamy macrophages and reactive fibroblastic proliferation.

RHABDOMYOSARCOMA

• Malignant mesenchymal tumor with skeletal muscle differentiation
• In childhood, two main types

image embryonal (eRMS)
image alveolar (ARMS)

• Pleomorphic type affects adults

EMBRYONAL RHABDOMYOSARCOMA

Epidemiology

• Commonest pediatric soft tissue sarcoma
• Most <10 yrs

image 50% <5yrs
image 5% <1 yr

Genetics

• 11p15 loss well-reported
• Not diagnostically useful
• No characteristic fusion transcript

Clinical features

• Despite skeletal muscle differentiation, only rarely (5%) arise in skeletal muscle of extremities
• 50% head and neck
• 30% genitourinary

image including paratesticular

• Remainder from wide range of sites

image including bile ducts and retroperitoneum

• Clinical features according to site

Histopathological features (Figs 6.26–6.31)

• Sheets of immature round to ovoid to spindle mesenchymal cells (rhabdomyoblasts)
• Variably cellular
• Variably loose stroma
• Variable degrees of morphological skeletal muscle differentiation

image strap cells
image tadpole cells
image spider cells

– differentiation especially prominent postchemotherapy

• May be predominantly immature mesenchymal cells morphologically

image small ovoid cells (‘small round blue cells’)
image stellate cells

• Spindle cell variant

image paratesticular and head and neck

– predominant spindle cells

· fascicles
· whorls
· storiform

• Botryoid variant

image eRMS affecting the wall beneath an epithelial surface

– vagina, bladder, bile ducts

image Intraluminal polypoid growth pattern macroscopically
image Loose myxoid stroma
image More highly cellular immediately beneath epithelium

– cambium layer

• Anaplastic / pleomorphic variant

image nuclear enlargement, hyperchromasia and anaplasia

image

Fig. 6.26

image

Figs 6.26–6.27 Macroscopic photographs of bladder and soft-tissue rhabdomyosarcomas, demonstrating poorly circumscribed, infiltrating lesions of viable cream-colored tumor.

image

Fig. 6.28

image

Fig. 6.29

image

Fig. 6.30

image

Figs 6.28–6.31 Photomicrographs of embryonal rhabdomyosarcomas, demonstrating ovoid to spindled tumor cells in a loose background stroma, with patchy and variable cytoplasmic eosinophilic rhabdomyomatous differentiation. The cellularity is often variable but is usually most marked immediately beneath the epithelial layer.

Immunohistochemical staining (Figs 6.32–6.33)

• Vimentin+
• Desmin cytoplasmic +
• Myogenin nuclear +

image all RMS show myogenin expression

– more widespread expression in ARMS (usually >70%+) compared to eRMS (usually <30%+)
– may be very focal in a limited sample such as core biopsy

• MyoD1 nuclear+

image cases with least myogenin+ show nuclear MyoD1+

• Myoglobin+ in well-differentiated cells
• Other markers may show aberrant expression
• Myogenin and MyoD1 >90% specific

image may also be positive in reactive myocytes (Morotti et al 2006)

image

Fig. 6.32

image

Figs 6.32–6.33 Photomicrographs of embryonal rhabdomyosarcomas, immunostained to demonstrate cytoplasmic expression of desmin and patchy nuclear expression of myogenin.

Differential diagnosis and pitfalls

• Marked pleomorphism may be a feature of a subgroup of eRMS in childhood with more aggressive course
• Sclerosing subtype also reported in childhood (Chiles et al 2004)

image hyalinized, matrix-rich stroma
image mixed ERMS-ARMS histology
image lack strong myogenin staining
• Postchemotherapy, eRMS may demonstrate marked differentiation with extensive eosinophilic cytoplasm

image presence of residual differentiated cells not associated with adverse prognosis
image presence of areas of morphologically poorly differentiated RMS are associated with poor prognosis
image in almost all cases, desmin / myogenin staining demonstrates scattered small cells and positive staining cells within the background

– clinical significance uncertain

ALVEOLAR RHABDOMYOSARCOMA

• Clinically more aggressive variant of RMS
• Alveolar architecture not always present
• Characteristic gene fusion transcript in the majority of cases (see below)
• Approx 20% of all RMS

Genetics

• t(2;13)(q35;q14) PAX3-FKHR
• t(1;13)(p36;q14) PAX7-FKHR
• Approx 80–90% demonstrate one of the above fusion transcripts

image diagnostic
image detectable by molecular techniques including

– FISH with FKHR break apart probes
– RT-PCR for fusion transcript detection

• Overall about 60% show PAX3-FKHR, 20% PAX7-FKHR, and 20% are fusion-negative (Barr et al 2006)

Clinical features

• Rapidly growing mass lesion
• Almost any site

image extremities 40%

• Symptoms according to site
• May present with disseminated disease with or without identifiable primary site
• Bone marrow metastases

Specific issues of specimen handling

• Fusion transcript detection is of diagnostic, prognostic and therapeutic importance and molecular studies mandatory

Histopathological features (Figs 6.34–6.37)

• Primitive mesenchymal cells
• Round cells with variably fibrous stroma
• Classical alveolar pattern

image fibrovascular septa
image tumor cell nests

– dyscohesive
– tumor cells surround margins of nests

• Solid variant

image sheets of round tumor cells
image no septae or stroma formation

image

Fig. 6.34

image

Fig. 6.35

image

Fig. 6.36

image

Figs 6.34–6.37 Photomicrographs of alveolar rhabdomyosarcomas, demonstrating sheets and nests of round to ovoid tumor cells in a variably fibrous stroma, which may show an obvious nested (alveolar) pattern, or a solid pattern of growth.

Immunohistochemical staining (Figs 6.38–6.39)

• Myogenic markers (see eRMS)
• Diffuse, strong nuclear Myogenin+
image

Fig. 6.38

image

Figs 6.38–6.39 Photomicrographs of alveolar rhabdomyosarcomas, immunostained to demonstrate strong and diffuse nuclear expression of myogenin in the majority of tumor cells.

Differential diagnoses and pitfalls

• Since the introduction of routine molecular testing the relative prevalence of morphological spectrum of ARMS has expanded
• Some cases previously thought to be eRMS on morphological grounds found to have translocation of ARMS since introduction of routine molecular testing
• Morphological pattern may be non-diagnostic in small needle biopsy specimens

image mixed eRMS / ARMS patterns exist as variant of ARMS

• Histologic features show a limited correlation with PAX/FKHR fusion status (Parham et al 2007)

image only totally solid alveolar architecture is associated with absence of PAX/FKHR fusion products
image no morphological features predict any particular fusion type

EXTRASKELETAL MYXOID CHONDROSARCOMA

Epidemiology

• Mainly adults

image pediatric cases well reported

Genetics

• t(9;22)(q22;q12) in >50%

image CHN-EWS fusion

• t(9;17)(q22;q11) in a minority

image RBP56-CHN

• Diagnostic when present

Clinical features

• Mass in deep soft tissues of limbs / limb girdle

image also trunk, head and neck

• 90% 5-year survival

image 40% long-term (15-year) mortality

• Local recurrence and metastases

Histopathological features

• Gelatinous nodules with fibrous septae, cysts, hemorrhage
• Nests of chondromyxoid stroma

image hypovascular stroma

• ‘Floating’ nests, cords or clusters of tumor cells

image more cellular at periphery
image uniform round-ovoid nuclei
image eosinophilic vacuolated cytoplasm
image few mitoses

• 30% show highly cellular sheets

image morphologically similar to other small ovoid cell tumors such as PNET

– cellular variant

• Epithelioid and anaplastic variants

Immunohistochemical staining

• Non-diagnostic
• Vimentin+
• S100, CK, EMA variable in a minority

Differential diagnoses and pitfalls

• May show focal rhabdoid phenotype but different molecular and immunostaining
• Large size, anaplasia and rhabdoid features may be associated with worse prognosis

DESMOPLASTIC SMALL ROUND CELL TUMOR

Epidemiology

• Children and young adults
• M > F

Genetics

• Characteristic and diagnostic
• t(11;22)(p13;q12)

image EWS-WT1 fusion

Clinical features

• Usually presents with disseminated abdominal disease

image now reported at many other sites

• Presentation depends on site
• Aggressive

image poor prognosis

Histopathological features (Figs 6.40, 6.41)

• Infiltrative growth

image desmoplastic stroma

– spindle cell
– variably collagenous
– variably vascular

image nests of tumor cells

– uniform ovoid cells
– hyperchromatic
– little cytoplasm

· may show intracytoplasmic inclusions
· may show crush type artefact

– mitoses, necrosis

image

Fig. 6.40

image

Figs 6.40–6.41 Photomicrographs of a desmoplastic small round cell tumor. The tumor shows infiltrative growth and is composed of nests of small, uniform, ovoid cells, within a variably desmoplastic stroma.

Immunohistochemical staining (Figs 6.42, 6.43)

• Polyphenotypic expression of nest cells

image epithelial

– CK, EMA

image muscle

– desmin

· dot-like intracytoplasmic

– vimentin

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