mast cell leukemia with rapidly progressing portal hypertension

Case Report

Mast cell leukemia with rapidly progressing portal hypertensionpin_2451 817..822

Masayuki Yoshida,1 Yuji Nishikawa,1 Yohei Yamamoto,1 Yuko Doi,1 Takuo Tokairin,1,2 Toshiaki Yoshioka,1

Yasufumi Omori,1 Atsushi Watanabe,3 Naoto Takahashi,3 Tomoko Yoshioka,3 Ikuo Miura,4 Ken-ichi Sawada3

and Katsuhiko Enomoto1

1Department of Molecular Pathology and Tumor Pathology and 3Division of Hematology and Oncology, Departmentof Medicine, Akita University Graduate School of Medicine, 2Department of Pathology, Nakadori General Hospital,Akita and 4Division of Hematology and Oncology, Department of Internal Medicine, St Marianna University School ofMedicine, Kawasaki, Kanagawa, Japan

Reported herein is an autopsy case of mast cell leukemia,a rare form of systemic mastocytosis, complicated withportal hypertension. A 52-year-old woman presented withurticaria-like skin symptoms, anemia, and thrombocytope-nia. Atypical mast cells (CD2+, CD25+, CD117+) with toluidineblue metachromasia were found in the peripheral blood andon bone marrow aspiration smears. Chemotherapy withcytosine arabinoside and idarubicin was ineffective and thepatient died of multi-organ failure with rapidly progressinghepatosplenomegaly and large-volume ascites 3 monthsafter admission. At autopsy the bone marrow, spleen, liver,and lymph nodes were extensively infiltrated by atypicaltumor cells with occasional bi- or multi-lobated nuclei. Theywere positive for mast cell tryptase and possessed an acti-vating mutation of the c-kit gene (D816V). Ascites (2200 mL)and non-ruptured esophageal varices with submucosal hem-orrhage indicated the presence of severe portal hyperten-sion. Although there was no evidence of liver cirrhosis, thehepatic sinusoids were clogged with tumor cells, with atendency to be more severe in the perivenular areas, and thelumens of central veins were obliterated by tumor cell infil-tration. The present case demonstrates that non-cirrhoticportal hypertension due to blocking of sinusoidal andvenous flow could be a serious complication in mast cellleukemia.

Key words: hepatic involvement, mast cell leukemia, non-cirrhotic portal hypertension

Mastocytosis is a generic term for heterogeneous disorderscharacterized by abnormal growth and accumulation of mast

cells in the skin (cutaneous mastocytosis) or extracutaneousorgans (systemic mastocytosis).1–3 Mast cell leukemia is anextremely rare form of systemic mastocytosis, with an inci-dent of only 1% among adult patients with systemic masto-cytosis in a recent retrospective study.4 This subtype ischaracterized by severe bone marrow involvement, appear-ance of circulating mast cells in the peripheral blood, multipleorgan dysfunction, and an aggressive clinical course.5–7 Thenumber of circulating neoplastic mast cells in the peripheralblood varies from case to case in mast cell leukemia and, ifthe mast cells comprise <10% of the circulating nucleatedcells, it is called the aleukemic variant.2,8

One of the intriguing features of systemic mastocytosis isits propensity to cause portal hypertension.9 The mechanismof mastocytosis-associated portal hypertension, however, isnot well understood. Although liver fibrosis has been docu-mented in some cases of systemic mastocytosis, the devel-opment of cirrhosis is rare.9–11 Here we describe an autopsycase of mast cell leukemia complicated with severe non-cirrhotic portal hypertension and discuss the possible causesof portal hypertension.

CLINICAL SUMMARY

A 52-year-old woman was admitted to a community hospitalbecause of moderate-grade fever and urticaria-like cutane-ous symptoms. Complete blood count showed moderateanemia, thrombocytopenia, and eosinophilia, with a hemo-globin concentration of 8.7 g/dL, a platelet count of 74 000/mm3, white blood cell count of 5400/mm3, and a differentialcount of 37% eosinophils. Hemophagocytosis was noted inthe bone marrow aspiration smears. Her medical historyincluded appendicitis, IgA nephropathy (12 years previously),right ovarian cyst, and uterine leiomyomas.

Correspondence: Yuji Nishikawa, MD, PhD, Department of Molecu-lar Pathology and Tumor Pathology, Akita University GraduateSchool of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan. Email:[email protected]

Received 20 April 2009. Accepted for publication 16 July 2009.© 2009 The AuthorsJournal compilation © 2009 Japanese Society of Pathology

Pathology International 2009; 59: 817–822 doi:10.1111/j.1440-1827.2009.02451.x

After being treated with high-dose corticosteroids, thepatient was transferred to Akita University Hospital. Therewas mild splenomegaly, but no hepatomegaly was presentand the urticarial skin lesions had disappeared. Laboratoryfindings included a hemoglobin concentration of 7.8 g/dL,platelet count of 58 000/mm3, white blood cell count of 5400/mm3, total protein level of 5.5 g/dL, albumin level of 3.4 g/dL,g-globulin level of 0.64 g/dL, urea nitrogen level of 71.8 mg/dL, creatinine level of 4.8 mg/dL, soluble interleukin-2 recep-tor level of 25 400 U/mL, histamine level of 690 nmol/L, andurea histamine level of 4500 nmol/L.

A small number of atypical cells were found in the periph-eral blood, but the incidence was no more than 5% of whitecells. Bone marrow aspiration and biopsy showed that therewas an increased number of atypical cells (60% of nucleatedcells) with bi- or multi-lobed nuclei and basophilic cytoplasmicgranules (Fig. 1a). Although these atypical cells containedabundant azurophilic granules, they were negative formyeloperoxidase and a-nanaphthyl butyrate esterase, butfaintly reacted with naphthol-ASD-chloroacetate esteraseand showed metachromasia on toluidine blue stain. Flowcytometry showed that the atypical cells were positive forCD2, CD13, CD25 (a chain of the interleukin-2 receptor), andCD117 (c-Kit), and negative for CD33 and CD34. The karyo-type of tumor cells obtained from the bone marrow wasnormal. The non-neoplastic bone marrow cells did not showany dysplastic changes. A bone marrow biopsy demon-strated that most of the bone marrow space was replaced byatypical cells, without evidence of fibrosis (Fig. S1a,b).

The patient was diagnosed with mast cell leukemia andreceived two courses of chemotherapy with cytosine arabi-noside and idarubicin. Bone marrow biopsy after the chemo-therapy showed that 56% of the nucleated cells werecomposed of tumor cells. Splenomegaly had progressedrapidly, and hepatomegaly, as well as massive ascites, haddeveloped, suggesting the presence of portal hypertension.Ultrasound examination of the liver showed narrowing ofhepatic veins. There was progressive hyperbilirubinemia,while the levels of transaminases and alkaline phosphataseremained normal. The patient died of systemic infection andmultiple organ failure 3 months after admission.

PATHOLOGICAL FINDINGS

The patient had severe jaundice and the abdominal cavitycontained serosanguineous ascites (2200 mL). Markedhepatomegaly (2100 g; Fig. S2a) and splenomegaly withseveral foci of acute infarcts (915 g; Fig. S2b) were found,but no discrete tumors were present in either organ. Thepara-aortic lymph nodes were mildly swollen. Numerousvarices and submucosal hemorrhage were noted in the lowerpart of the esophagus, compatible with the presence of

severe portal hypertension (Fig. S2c). Small ulcers in thestomach (antral region) and duodenum, and longitudinalulcers with pseudomembranous debris in the cecum andtransverse colon, which might have been attributable to theadverse effect of the intense chemotherapy, were observed.The kidneys were markedly atrophic (left, 60 g; right, 50 g)and showed characteristics of dialysis-associated cysticdisease.

Microscopically, atypical tumor cells replaced most of thebone marrow space and encroached on trabecular bones(Fig. 1b). The tumor cells were medium-sized to large, withan irregular, sometimes bilobed or multilobed, nucleus, andcontained slightly eosinophilic or amphophilic cytoplasm(Fig. 1c) with toluidine blue metachromasia (data not shown).There was no significant increase in reticulin or collagenfibers (Fig. 1d). Similar cells also diffusely infiltrated theenlarged spleen and liver. They were also found in the sinu-soidal spaces of the swollen para-aortic lymph nodes. Immu-nohistochemistry was performed on formalin-fixed paraffin-embedded sections, using the peroxidase-based Envisiontechnique (Dako, Glostrup, Denmark), with the antibodiesagainst leukocyte common antigen (LCA; Dako), mast celltryptase (Millipore (Chemicon/Upstate/Linco), Billerica, MA,USA), CD117 (Dako), CD68 (Dako), CD43 (Bio-ScienceProducts, Emmenbrucke, Switzerland), myeloperoxidase(Dako), CD20 (Dako), CD3 (Dako), CD34 (Dako), and Bcl-2(Dako). The tumor cells were positive for LCA, mast celltryptase (Fig. 2a), and CD117 (Fig. 2b), whereas they werenegative for CD68, CD43, myeloperoxidase, CD20, CD3,CD34, and Bcl-2, further confirming the features of mast celldifferentiation. A similar immunophenotype was confirmed inthe tumor cells obtained by biopsy (Fig. S1c–e). Ultrastruc-turally, the tumor cells showed irregular nuclear contours,and the cytoplasm contained numerous granules containingdiscrete scrolls (Fig. S3). Direct sequencing of the c-kit proto-oncogene was performed, according to the previouslydescribed method, on DNA extracted from splenic tissue thatwas diffusely infiltrated by tumor cells.12 The result indicatedthe presence of an activating mutation (D816V) of the gene(Fig. 2c).

One of the salient features of the present case was markedportal hypertension that progressed rapidly before thepatient’s death. Although the mucosal surfaces of theesophagus were intact, engorged varices and hemorrhage inthe submucosa were present (Fig. S2c,d). The walls of thevaricose veins were extremely thin, and some of themappeared to be discontinuous. In the liver the portal tract wasslightly enlarged with a subtle increase in collagen, but therewas no evidence of lobular remodeling or cirrhosis(Fig. 3a,b). Although the tumor cells diffusely infiltrated theliver parenchyma including the portal tract, the infiltration wasmore prominent in the perivenular area, where the sinusoidalspaces were clogged with tumor cells (Fig. 3c,d). The tumor

818 M. Yoshida et al.

© 2009 The AuthorsJournal compilation © 2009 Japanese Society of Pathology

Figure 1 Microscopy of the bone marrow. (a)Bone marrow aspirate smear performed beforechemotherapy (Wright-Giemsa). Numerous largeblasts with atypical nuclei and basophilic cytoplas-mic granules are seen. (b–d) Sections of bonemarrow obtained at autopsy. (b) The bone marrowspace is largely occupied by tumor cells. (c) High-power magnification shows diffuse infiltration bymedium–large tumor cells with hyperchromaticirregular nuclei. (d) There is no discernible increasein reticulin or collagen fibers (reticulin).

Figure 2 Immunohistochemistry and directsequencing analysis of the c-kit proto-oncogene ofthe tumor. (a,b) Immunohistochemistry was per-formed on tumor tissues infiltrating the bonemarrow. The tumor cells are strongly positive for (a)mast cell tryptase and (b) CD117 (c-Kit). (c)Genomic DNA was extracted from the splenictissue obtained at autopsy and analyzed for thesequence at codon 816 of the c-kit gene. There is amutant signal on both strands (left, plus strand;right, minus strand), confirming the presence of anactivating mutation (D816V).

Mastocytosis with portal hypertension 819


Figure 3 Hepatic involvement by the tumor. (a) Tumor cells diffusely infiltrate the liver, especially in the centrilobular zone (C), with slightenlargement of the portal tract (P). (b) There is no evidence of lobular remodeling or fibrosis (elastica-Masson trichrome). (c) Mild–moderateinfiltration by tumor cells is present in the portal tract. (d,e) Tumor cell infiltration is more prominent in the perivenular area, where the sinusoidalspaces and central veins are clogged with tumor cells. (f) There is no increase in collagen fibers in the wall of central veins (elastica-Massontrichrome). (g,h) The walls of thickened central veins contain loosened reticulin fibers, which are separated by infiltrating tumor cells (reticulin).



cells densely infiltrated the central veins, resulting in wallthickening and obliteration of the luminal structures (Fig. 3e),without a discernible increase in collagen (Fig. 3f). The thick-ened walls contained loosened reticulin fibers, which wereseparated by infiltrating tumor cells (Fig. 3g,h).

DISCUSSION

We describe here a case of systemic mastocytosis, whichwas characterized by proliferation of atypical cells with tolui-dine blue metachromasia, marked nuclear polymorphism,and rapid development of non-cirrhotic portal hypertension.Immunophenotyping on flow cytometry and immunohis-tochemistry showed that the tumor cells expressed generalmarkers for mast cells (c-Kit and mast cell tryptase), as wellas markers for neoplastic mast cells (CD2 and CD25). Ultra-structurally the tumor cells contained small cytoplasmic gran-ules containing discrete scrolls, structures typical of mastcells. An activating mutation of the c-kit gene (D816V) wasdetected in the tumor, further confirming the diagnosis.Approximately 60% of nuclear cells of the bone marrow wereestimated to be tumor cells in the biopsy specimen, whilethere were only a small number of circulating tumor cells. Thesystemic mastocytosis in the present case could therefore beclassified into the aleukemic variant of mast cell leukemia,according to the World Health Organization classification.2

The clinical course was aggressive and the patient died3 months after admission. Sperr et al. reported on the rela-tionship between the extent of bone marrow infiltration bymast cells and the prognosis: patients with >20% of mastcells generally have more rapid disease progression thanthose with less.13 It has also been noted that, regardless ofthe percentage of circulating mast cells, extensive involve-ment of the bone marrow with neoplastic mast cells should beconsidered to be a sign of aggressive disease in malignantmastocytosis.6

Neoplastic mast cells could exhibit a variety of cytologicalproperties: metachromatically granulated blast (blast-likemorphology, some metachromatic granules), atypical mastcell type II (promastocytes; polymorphic, bi-lobed or multi-lobed nuclei, typical metachromatic granules), atypical mastcell type I (spindle-shaped, hypogranulated with focal granuleaccumulation), and typical (mature) tissue mast cells.13,14 Inthe present case the proliferating mast cells possessed thecharacteristics of the metachromatically granulated blast aswell as atypical mast cell type II, while spindle-shaped atypi-cal mast cells (type I), which appear most frequently in indo-lent systemic mastocytosis, were not found. In cases ofaggressive variants of systemic mastocytosis (aggressivesystemic mastocytosis and mast cell leukemia), the neoplas-tic mast cells tend to be immature and exhibit bi- or multi-lobed nuclei or resemble granulated blast-like cells.5,15,16 It

has been shown that, if the percentage of atypical mast celltype II is >10% of neoplastic mast cells in bone marrowsmears, the prognosis becomes significantly worse.13

Systemic mastocytosis has been reported to be compli-cated with portal hypertension.9,10 Several mechanisms havebeen proposed for mastocytosis-associated portal hyperten-sion, such as portal fibrosis,9,17–19 subendothelial collagendeposition,18 increased splenic blood flow,20 hepatic venousflow block,9,19 and mast cell infiltration.9,17–22 Portal fibrosisand subendothelial collagen deposition might be partlyexplained by the effect of mast cell-derived factors (e.g.chymase, tryptase, tumor necrosis factor-a, fibroblast growthfactor, platelet-derived growth factor, and transforminggrowth factor-b) on fibroblast proliferation and increased col-lagen synthesis.23 Severe liver fibrosis with lobular remodel-ing, however, which could solely explain portal hypertension,is rare in systemic mastocytosis.9–11 The principal mecha-nisms of portal hypertension in the present case appeared tobe blocking of sinusoidal and venous flow by neoplastic mastcell accumulation and infiltration. It has been shown that, inaggressive (malignant) systemic mastocytosis, portal andlobular infiltration of neoplastic mast cells is more frequentthan in non-aggressive types of systemic mastocytosis.10

Although mast cell infiltration is generally more prominent inthe portal tract, sinusoidal accumulation could be more pro-found.10 Furthermore, obliteration of the central veins withloose connective tissue infiltration by mast cells, similar to thefinding in the present case, has been documented in severalcases of systemic mastocytosis.9 Because mast cells arerarely found in normal liver parenchyma,24 neoplastic mastcells might have acquired the capacity to adhere to sinusoidalendothelial cells. It is of interest to note that abnormal mastcells in systemic mastocytosis, including the present case,express a cell adhesion molecule, CD2 (LFA2), that is absentin normal mast cells.25,26 Because sinusoidal endothelial cellsexpress CD58 (LFA3), a ligand for CD2,27,28 the sinusoidalaccumulation of neoplastic mast cells might be partlyexplained by their aberrant CD2 expression.

REFERENCES

1 Valent P, Horny HP, Escribano L et al. Diagnostic criteria andclassification of mastocytosis: A consensus proposal. Leuk Res2001; 25: 603–25.

2 Horny HP, Metcalfe DD, Bennett JM et al. Mastocytosis. In:Swerdlow SH, Campo E, Harris NL et al., eds. World HealthOrganization Classification of Tumours of Hematopoietic andLymphoid Tissues. Lyon: IARC Press, 2008; 54–63.

3 Valent P, Sperr WR, Schwartz LB, Horny HP. Diagnosis andclassification of mast cell proliferative disorders: Delineationfrom immunologic diseases and non-mast cell hematopoieticneoplasms. J Allergy Clin Immunol 2004; 114: 3–11; quiz 12.

4 Lim KH, Tefferi A, Lasho TL et al. Systemic mastocytosis in 342consecutive adults: Survival studies and prognostic factors.Blood 2009; 113: 5727–36.

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13 Sperr WR, Escribano L, Jordan JH et al. Morphologic propertiesof neoplastic mast cells: Delineation of stages of maturation andimplication for cytological grading of mastocytosis. Leuk Res2001; 25: 529–36.

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16 Chott A, Guenther P, Huebner A et al. Morphologic and immu-nophenotypic properties of neoplastic cells in a case of mast cellsarcoma. Am J Surg Pathol 2003; 27: 1013–19.

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18 Ghandur-Mnaymneh L, Gould E. Systemic mastocytosis withportal hypertension. Autopsy findings and ultrastructural studyof the liver. Arch Pathol Lab Med 1985; 109: 76–8.

19 Narayanan MN, Liu Yin JA, Azzawi S, Warnes TW, Turck WP.Portal hypertension and ascites in systemic mastocytosis. Post-grad Med J 1989; 65: 394–6.

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SUPPORTING INFORMATION

Additional Supporting Information may be found in the onlineversion of this article:

Figure S1 Microscopic and immunohistochemical findings ofthe bone marrow biopsied before chemotherapy. (a) Most ofthe tissue is replaced by tumor cells. (b) There is no evidenceof bone marrow fibrosis (reticulin). (c–d) Tumor cells arepositive for (c) mast cell tryptase and (d) CD117, but negativefor (e) CD68.

Figure S2 Autopsy findings of the liver, spleen, and esopha-gus. (a) Marked hepatomegaly (2100 g) without cirrhoticchange. (b) The spleen is large (915 g) and several foci ofacute infarcts are seen on cut surfaces. (c) In the loweresophagus, dark discoloration of the mucosa is seen. (d) Inthe lower esophagus, there are numerous varicose veins,some of which are hemorrhagic.

Figure S3 Electron microscopy of tumor cells in the spleen.The neoplastic mast cells have multi-lobed or irregularlyindented nuclei. There are cytoplasmic granules containingdiscrete scrolls (inset, arrows), characteristic of mast cells.

Please note: Wiley-Blackwell are not responsible for thecontent or functionality of any supporting materials suppliedby the authors. Any queries (other than missing material)should be directed to the corresponding author for thearticle.



mast cell leukemia with rapidly progressing portal hypertension

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