Atypical Mononuclear Cells Research Articles

Pink pseudohypopyon as a presenting feature of large B‐cell lymphoma

AbstractPurpose To describe the clinicopathologic features of a patient who developed an anterior chamber (AC) infiltrate mimickina pink pseudohypopyon as a presenting feature of large B‐cell lymphoma.Methods The clinical and pathologic findings in a patient with AC infiltrates secondary to systemic B‐cell lymphoma are reviewed. Main outcome measurements were clinical observation and cytologic/flow cytometric examination of the infiltrate after AC aspiration.Results A 51‐year‐old woman was evaluated for decreased vision in her right eye. On examination, her visual acuity was 20/30 in the right eye (RE) and counting fingers in the left eye. Abnormalities were confined to the RE. Slit lamp examination revealed +1 AC cells with a pink pseudohypopyion occupying 40% of the AC. The iris was corrugated and had small new vessels in the stroma. An anterior chamber aspirate was performed, and 0.8 ml of fluid was obtained. The sample was formed by 32% of lymphocytes and 54% of neutrophils. B‐lymphocytes were predominant over T‐lymphocytes (91% and 8%, respectively). Cytologic examination showed scattered atypical mononuclear cells. Immunohistochemical stains were positive for CD19 in the atypical cells. Flow cytometric immunophenotyping revealed a clonal, kappa restricted population of B‐lymphocytes comprising 97% of the viable cells in the sample. These results were consistent with a large B‐cell extranodal lymphoma.Conclusion Anterior chamber/iris infiltration from systemic lymphoma is exceedingly rare, present in less than 10% of patients. Herein, we describe a patient with systemic lymphoma in whom the first manifestation was a pink pseudohypopyon.

Lymphomatoid Granulomatosis Presenting with Gingival Involvement in an Immune Competent Elderly Male

Lymphomatoid granulomatosis (LYG) represents a B cell lymphoproliferative disorder that appears to be driven by infection of the lesional cells by Epstein-Barr virus (EBV). Although not a common condition, the overwhelming majority of cases affect the lungs and mediastinal lymph nodes. Oral mucosal involvement has been documented in only one other report. We describe an 82-year-old man who developed a chronic oral ulcer following extraction of a mandibular molar tooth. Biopsy of the ulcer identified large atypical mononuclear cells that had a B cell immunophenotype and were associated with the walls of several arterioles in the sample. In situ probes for EBV-encoded small RNA showed prominent labeling of these large cells, suggesting the possibility of LYG. Imaging studies identified mediastinal and hilar lymphadenopathy on CT imaging, while PET scans showed hypermetabolic activity in the lymph nodes as well as the left mandible. Based on these findings, a diagnosis of LYG was made and the patient was treated with rituximab, an anti-CD20 monoclonal antibody, combined with a chemotherapeutic regimen consisting of etoposide, prednisone, vincristine, cyclophosphamide and doxorubicin. After three cycles of therapy, the oral ulcer resolved significantly, as well as the areas of hypermetabolic nodal activity. Remission continued for 3years, however the patient eventually developed non-small cell carcinoma of the lung and expired as a result of that tumor.

Measurement and cellular sources of the soluble interleukin-2 receptor in primary central nervous system lymphoma

The aims of this study were to determine the diagnostic utility of the serum levels of the soluble interleukin 2 receptor (sIL-2R) as a tumor marker of primary central nervous system lymphoma (PCNSL) and to investigate the cellular source of sIL-2R using immunohistochemical staining. The serum sIL-2R levels of 37 samples from suspected PCNSL patients were measured. There were 13 patients with PCNSL and 24 patients with other diseases such as glioma, metastatic tumor, inflammation, or cerebrovascular disease. The serum sIL-2R levels of the PCNSL cases and other brain diseases were 629.5±586.0U/ml (mean±SD; range 189-2220U/ml) and 408.5±250.7U/ml (160-837U/ml), respectively. The serum sIL-2R levels of the two groups overlapped, and hence the difference between them was not significant. sIL-2R is the α subunit of IL-2R. It is also known as CD25, and is cleaved from its position in the cell membrane and released into the blood. CD25 expression was immunohistochemically detected in 7 of 11 PCNSL samples. Confocal laser microscopy revealed that CD25 signals were present in atypical cells and mononuclear cells. We concluded that both lymphoma cells and infiltrating T cells express CD25, which is one of the cellular sources of sIL-2R.

Canine intravascular lymphoma with overt leukemia

A 6-year-old spayed Labrador Retriever Mix dog was evaluated for a 2-week history of progressive generalized weakness and reluctance to stand. Physical examination revealed severe weakness with obtunded mentation, head tilt, bilateral nystagmus, and decreased vision. CBC findings included mild nonregenerative anemia, marked thrombocytopenia, and a few atypical mononuclear cells on the blood film. The cells were 15-30 μm in diameter and had round to oval to reniform centrally placed nuclei with stippled chromatin, prominent nucleoli, and abundant basophilic cytoplasm with numerous discrete vacuoles and, occasionally, small azurophilic granules. Similar cells were found in bone marrow. On histologic examination of tissues collected at necropsy, neoplastic cells were detected in bone marrow, hepatic sinusoids, cerebral and meningeal vessels, and in capillaries of the heart, renal interstitium, small intestinal submucosa, and muscularis, and alveolar septa. A small discrete mass in the right atrium consisted of similar neoplastic cells, and the spleen was diffusely infiltrated. Tissue distribution was suggestive of intravascular lymphoma. Neoplastic cells in tissue sections were immunoreactive for vimentin, CD18, CD45, and granzyme B and lacked immunoreactivity for cytokeratin. Neoplastic cells on bone marrow aspirate smears and blood films lacked immunoreactivity for CD3, CD79a, CD1c, CD11b, CD11c, CD11d, and E-cadherin. In the absence of immunophenotypic evidence for the neoplastic cells being derived from B-cell, T-cell, or histocytic/dendritic lineages and the lack of clonal antigen receptor gene rearrangement(s), along with positive immunoreactivity for granzyme B, a tumor of NK cells was considered likely. Based on current knowledge, this is the first report of canine intravascular lymphoma, of probable NK cell origin, with peripheral blood involvement.

Cutaneous metastasis of testicular choriocarcinoma, diagnosed by fine-needle aspiration cytology: A rare case report and review of the literature

Skin metastasis of testicular choriocarcinoma is very rare. Until now about nine cases have been reported in the English literature; however, only one of them has been diagnosed by fine-needle aspiration (FNA) cytology. Herein, we report our experience with FNA cytology diagnosis of a metastatic testicular choriocarcinoma to the skin of chin. The combination of highly atypical mononuclear cells (cytotrophoblasts) and multinucleated malignant cells (syncytiotrophoblasts) are characteristic of metastatic tumor in a known case of choriocarcinoma of testis.

Traumatic Ulcerative Granuloma With Stromal Eosinophilia: Report of a Case and Literature Review

Traumatic eosinophilic granuloma with stromal eosinophilia is a rare entity that affects the oral mucosa and has a controversial etiologic pathogenesis. Histologically, these lesions are characterized by a dense and deeply infiltrative lymphoproliferation showing epitheliotropic characteristics and massive eosinophilia. Frequently, a population of mitotically active, atypical mononuclear cells can be noted. This report describes a case of traumatic eosinophilic granuloma with stromal eosinophilia in the floor of the mouth of an 88-year-old man. The phenotypic and genotypic profiles of the inflammatory infiltrate and large atypical mononuclear cells, using immunohistochemical and polymerase chain reaction-based molecular analysis, were analyzed.

Regression of CD30+ cutaneous anaplastic large-cell lymphoma with denileukin diftitox

To the Editor: A 46-year-old woman presented with rapid development of ulcerating nodules on her right leg during the 3 months before presentation (Fig 1, A). A punch biopsy specimen of one of two 2-cm nodules revealed dense nodular infiltrates of atypical mononuclear cells with pleomorphic nuclei and moderate pink cytoplasm in the mid and deep reticular dermis (Fig 2, A). Mitotic figures and necrotic cells were scattered throughout the lesion. These atypical cells stained positively for CD30 (Fig 2, B) and CD3, but negatively for CD20, S-100, CD1a, and anaplastic lymphoma kinase.

Juvenile myelomonocytic leukemia characterized by cutaneous lesion containing Langerhans cell histiocytosis-like cells

We present a 1-year-old boy who developed a cutaneous lesion on the trunk and hepatosplenomegaly. Laboratory examination showed leukocytosis with peripheral blasts, atypical monocytosis, anemia, hyper IgG, and a mild elevation of C-reactive protein. Clinical features and skin biopsy findings matched the diagnostic criteria of both juvenile myelomonocytic leukemia (JMML) and Langerhans cell histiocytosis (LCH). Histopathology revealed atypical mononuclear cells that had infiltrated around vessels throughout the dermis in a skin biopsy specimen. These cells were CD1a (+), S-100 (+), CD68 (+), CD207 (-), lysozyme (+), and myeloperoxidase (-). The diagnosis of JMML was confirmed by detection of spontaneous colony formation and granulocyte-macrophage colony-stimulating factor hypersensitivity in vitro, and a somatic NRAS point mutation. Transplantation of bone marrow from an HLA-matched unrelated donor was performed, and the marrow was successfully engrafted. The cutaneous lesion and hepatosplenomegaly were improved at the time of discharge. It is often difficult to distinguish between JMML and LCH-like infiltrates by assessing clinical and light microscopic features of various cutaneous lesions. In the current case, molecular biological analysis enabled us to develop a precise diagnosis.

LA MALADIE DE KIKUCHI-FUJIMOTO

Background : The necrotizing histiocyte lymphadenitis is a disease of unknown cause. Clinicians should be aware of this uncommon disease in order to differentiate it from lymphoma, infectious adenitis, and collagenosis. Case report: A 24-year-old woman consulted for a right cervical mass which had developed rapidly with no associated symptom. Laboratory results were normal. The gangular biopsy confirmed the diagnosis of necrotizing hymphanditis. Discussion : Necrotizing histiocyte lymphadenitis is generally observed in young women in their twenties. There has been no predominant ethnic background. Clinically, it is characterized by lymphadenitis of one or more lymph nodes, predominantly in the cervical region. the Laboratory tests are normal excepting for discrete signs of inflammation. Diagnosis anatomopathologic, ,the characteristic features include focal necrosis predominantly in the paracortical region with abundant karyorrhectic debris and atypical mononuclear cells around the necrotic zone (crescent-shaped histiocytes, plasmacytoid monocytes, and small lymphocytes and immunoblasts). The clinical course is generally spontaneously favorable in six months. Relapse is uncommon. Conclusion : The clinicopathologic picture can be confused with a malignant blood disease particularly lymphoma. Evolution is benign and healing without treatment is the rule.

Pagetoid Reticulosis After Radiotherapy of Primary Cutaneous Anaplastic Large-Cell Lymphoma

We describe a 60-year-old man with a history of primary cutaneous anaplastic large cell lymphoma on the chest, who presented with a new scaly red plaque on the same site 11 years after radiation therapy. Histological examination revealed a dense epidermotropic infiltrate of atypical mononuclear cells consistent with pagetoid reticulosis. Immunohistochemistry revealed the infiltrate to be CD4, CD8, and CD30. Remarkably, all the atypical cells were strongly CD30, and furthermore, the CD30 cells were found exclusively in the epidermis. In the initial cutaneous anaplastic large cell lymphoma lesion, the CD4, CD8, and focally CD30 atypical cells were well confined within the dermis with no epidermal component. To our knowledge, the present case seems to be the first description of pagetoid reticulosis presenting at the site of a previously treated dermal anaplastic large cell lymphoma. This case also represents an extreme presentation of epidermotropism and CD30 expression in pagetoid reticulosis.

Fatal HHV6 infection in an immunocompromised patient presenting with skin involvement

Infection with human herpesvirus-6 (HHV6) has a broad distribution in the human population, with a seroprevalence approaching 100% worldwide. Primary infection takes place during childhood, after which the virus remains latent mostly in lymphocytes and monocytes at various sites. Immunosuppression can result in viral reactivation, associated with clinical sequelae and even death. We report a case of a disseminated HHV6 infection in a 53-year-old patient, who was immunocompromised after allogeneic bone marrow transplant treatment for acute lymphocytic leukemia. Initially, he presented with a macular eruption of the skin, followed by involvement of other sites. Histopathologic analysis of skin biopsies revealed superficial perivascular large atypical mononuclear cells with intranuclear and intracytoplasmic inclusions. Most affected cells labeled with antibodies to CD3 and CD43 as lymphocytes, and some labeled with CD68 as macrophages. Polymerase chain reaction (PCR) studies of the blood, skin, liver, colon, cerebrospinal fluid and brain were positive for HHV6 virus. Additionally, the serologic titers for HHV6 were high. Viral particles were also detected by electron microscopy (EM) in the colon. Although rare, HHV6 virus may be an important pathogen in immunocompromised patients, and may present initially in the skin. Awareness of this infection is critical to diagnosis in acute settings.

Intracerebellar Granulocytic Sarcoma Presenting as a First Manifestation of Relapse in Chronic Myelogenous Leukemia (CML) During Imatinib Mesylate Therapy: A Case Report and Literature Review.

Abstract 4289 IntroductionGranulocytic sarcoma (GS) is an unusual solid tumor of extramedullary localization consisting of immature granulocytic precursors. It is mostly encountered in the course of acute myelogenous leukemia (AML), myelodysplastic or myeloproliferative disorders, with an estimated incidence of 7.9% in CML (Terjanian et al). GS can occur before, concomitantly, or after the overt development of these hematologic disorders. Most common localizations are lymph nodes, bones, skin and soft tissues, but there is paucity of published data of isolated intracranial GS manifesting as relapse in CML. Case reportA 34-year-old male with Philadelphia chromosome-positive (Ph+) CML diagnosed in August 2005 in the chronic phase of the disease. After initiation of imatinib therapy at doses of 400 mg/d he achieved complete hematologic, cytogenetic and molecular responses. He remained in clinical remission for 3 years when he presented with bifrontal headache and dizziness. Physical exam revealed no abnormalities. Peripheral blood count showed WBC 9,200/mm3 with normal differential and no immature forms, platelet 180,000/mm3, and hemoglobin 14.4 g/dl. Magnetic resonance imaging of the brain revealed a 3.8 cm enhancing mass lesion within the left cerebellar hemisphere. He underwent posterior fossa exploration with resection of the solid tumor. Microscopic examination of the cerebellar mass demonstrated a diffuse cellular infiltrate of atypical mononuclear cells with high nuclear to cytoplasmic ratios and fine, immature chromatin, consistent with blasts. Flow cytometric analysis confirmed that the majority of the cells in the specimen were composed of blasts which coexpressed the CD33 and CD4 markers. Fluorescence in situ hybridization analysis on the cerebellar tissue detected the presence of BCR/ABL rearrangement in 60% of nuclei. Taken together, the morphologic, immunophenotypic, and molecular features are diagnostic of a myeloid sarcoma representing transformation of chronic myeloid leukemia. DiscussionA literature search was performed to identify all cases of intracranial GS in patients with diagnosis of CML reported in medical literature. Only 3 cases were identified in the literature to date. This case appears to be the first described in the imatinib mesylate era. Table 1 summarizes the clinical data of these previously recorded cases and the present case.Table 1Case no.ReferenceAge / sexGS locationCML Status (systemic)No. years since DxPrior therapiesOutcome1Simpson et al, 198951 FLeft parietal lobeRelapse2.5-Hydroxyurea, busulfan, α-interferonAlive 4 months after cranial RT with no evidence of blastic transformation2Mahendra et al, 199440 MRight frontal lobeRelapse8.5-Busulfan, hydroxyurea -Allogeneic SCTDied 3.8 months after his allograft3Grondin et al, 199631 MMultiple brain nodulesRelapse1.5-HydroxyureaAlive immediately after whole brain RT with near complete resolution of brain lesions4Present case report34 MLeft cerebellar hemisphereRemission3.3-Imatinib mesylateDied 7 months after dx of intracranial relapse. Subsequent to tumor resection and posterior fossa RT, patient achieved a non-durable response, ultimately developing cerebellar and leptomeningeal relapsesAbbreviations: CML: chronic myelogenous leukemia, Dx: diagnoses, GS: granulocytic sarcoma, RT radiotherapy, SCT: stem cell transplantPharmacokinetic analyses (Pfeifer et al, Leis at al, Wolff et al) have demonstrated that imatinib poorly penetrates the blood–brain barrier, with resultant CNS drug levels significantly lower than corresponding plasma levels. Measured CSF levels were below the concentration required for 50% inhibition of the BCR–ABL tyrosine kinase activity, suggesting that Ph+ leukemic patients treated with this selective tyrosine kinase inhibitor are at high risk of CNS relapse even in the setting of complete remission of systemic disease.This case illustrates an unusual site of recurrence of CML. To our knowledge, this is the first case of a granulocytic sarcoma presenting as a solitary parenchymal brain tumor in a patient receiving imatinib for CML. Noticeably, CNS relapse occurred despite lack of systemic evidence of disease. As described in human and animal model studies this may be the result of effective systemic antileukemic activity of imatinib therapy, but with limited activity in the CNS. Poor penetration of imatinib into the cerebrospinal fluid may allow the CNS to become a sanctuary reservoir for relapse of Ph+ CML. Disclosures:No relevant conflicts of interest to declare.

T-Cell Receptor Gene Rearrangement and CD30 Immunoreactivity in Traumatic Ulcerative Granuloma With Stromal Eosinophilia of the Oral Cavity

Traumatic ulcerative granuloma with stromal eosinophilia (TUGSE) is an ulcerative lesion of the oral mucosa with unknown pathogenesis. A few recent case reports have demonstrated molecular evidence of T-cell clonality in TUGSE and CD30 immunoreactivity in the large atypical mononuclear cells, raising the possibility that a TUGSE subset may represent the oral counterpart of primary cutaneous CD30+ T-cell lymphoproliferative disorders. We examined the immunoreactivity for CD30 and T-cell receptor (TCR) gamma gene rearrangement in 37 TUGSE cases. Clonal TCR gene rearrangements were demonstrated in 7 (24%) of 29 cases with amplifiable DNA, and the morphologic features and CD30 immunoreactivity of these cases did not differ from those with polyclonal TCR gene rearrangements. Clinical follow-up was available for 5 of 7 TUGSE cases with clonal TCR gene rearrangement for an average period of 1.75 years after the initial biopsy or excision, and there was no evidence of local recurrence or development of systemic T-cell lymphoproliferative disorder. Without morphologic and/or clinical evidence of lymphoma, T-cell clonality and/or CD30 positivity in these lesions is not indicative of malignancy and should be interpreted with caution.

Maxillofacial mass as the first presentation of acute lymphoblastic leukemia in a nine-year-old girl

A nine-year-old girl complained of a maxillofacial mass and mild fever lower than 37.5 degrees C. A solid mass was detected in the right maxillary fossa by CT and sonographic examination, and the tumor extended backward into the infratemporal fossa without bony destruction. Laboratory studies showed a white blood cell (WBC) count of 31.6x10(9)/L, which increased progressively to 50.0x10(9)/L over the next several days. Peripheral blood smear revealed 92% lymphoblast with uneven bulk. A biopsy through the right labiogingival groove disclosed a submucosal homogeneous mass. Histologic examination under the microscope revealed atypical mononuclear cells with obvious atypia and nuclear divisions. Bone marrow puncture showed atypical lymphocytes with active proliferation. Immune phenotypic analysis by flow cytometry showed that malignant cells were positive for CD19, CD34, HLA-DR, CD38, CD22, CD58, CD45 and CD56. Real time RT-PCR revealed positive BCR/ABL arrangement. High-risk ALL was diagnosed and four stages of chemotherapies were given for nearly three years. After the induction of the chemotherapy, the facial mass disappeared. A bone marrow biopsy revealed that CR had been achieved since a month after chemotherapy's onset. The initial presentation of ALL as a maxillofacial mass is exceedingly rare. To the best of the authors' knowledge, this is the first reported case of ALL presenting as a maxillofacial lesion.

Hiv-Associated Lymphoma

A 39-year-old man with AIDS experienced worsening shortness of breath, cytopenia, and fever and was admitted to Baylor University Medical Center. The patient also reported symptoms of anorexia, diarrhea, abdominal pain, and generalized body pain. The physical examination showed cachexia; a large perineal Kaposi sarcoma tumor, as well as scattered Kaposi sarcoma lesions on his face, neck, back, and chest; dependent edema in the legs and scrotum; a scrotal ulcer; and abdominal distension with ascites and tenderness. No lymphadenopathy or hepatosplenomegaly was noted. A lung infiltrate and right-sided pleural effusion were evident, and the possibility of parapneumonic effusion was considered. A complete blood count demonstrated leukopenia (white blood cell count, 500 K/uL), anemia (hemoglobin, 8.6 g/dL), and thrombocytopenia (platelet count, 19,000 K/uL), with a virtual absence of CD4+ cells (<1%). The absolute lymphocyte count was 288 cells/L. HIV-1 RNA quantification by polymerase chain reaction was <50. The patient's blood cultures were also positive for Streptococcus viridans. The source of the infection was believed to be the skin, in association with Kaposi sarcoma. The patient was treated with broad-spectrum antibiotics, and follow-up blood cultures showed resolution of the infection. The pleural effusion was drained and sent for cytologic evaluation. Results showed highly atypical, pleomorphic lymphoid cells (Figures ​(Figures11 and ​and22). Usual B and T cell markers (CD3, CD5, CD10, CD15, CD20, CD79a, PAX5) were negative, and activation markers (CD30 and MUM1) were positive in this tumor. CD138 showed a minimal to no staining pattern (although most PELs show a positive reaction). The tumor proliferation marker MIB-1 (Ki-67) showed strong positivity, with staining of 75% of cells (Figure ​(Figure33). The cells were positive for human herpesvirus 8 (HHV8) and Epstein-Barr virus (EBV) (Figure ​(Figure44). The EBV copy number in the pleural fluid was 105,000/mL. Figure 1 (a) Highly cellular smear with multiple aggregates of mononuclear cells (×10, hematoxylin and eosin stain [H&E]). (b) Note the pleomorphic nature of the cells (×20, H&E). (c) Some of the cells show plasma cytoid features ... Figure 2 High-power view (×40, H&E) of primary effusion lymphoma. Note the multinucleated tumor cell with prominent macronucleoli (arrow) in a background of highly atypical pleomorphic mononuclear cells. Figure 3 Immunohistochemistry results showed positive staining (×10) for (a) CD30, (b) MUM1, and (c) MIB1 (75%). Figure 4 (a) Primary effusion lymphoma with a distinct, strong positive reaction to HHV8 (×10). (b) Ebstein-Barr virus–encoded small RNAs (EBER) staining showed scattered, slightly positive cells (×10). Although the differential diagnosis based on the clinical findings would include pyothorax-associated lymphoma, Burkitt lymphoma, lymphomatous effusion of disseminated lymphoma, malignant melanoma, and pleomorphic non–small cell carcinoma, the absence of HHV8 in each of these lymphomas eliminated them from consideration. Primary effusion lymphoma (PEL) was diagnosed.

Kikuchi-Fujimoto disease with aseptic meningitis

=Abstract= Kikuchi-Fujimoto disease was initially described as a self-limiting histiocytic necrotizing lymphadenitis in Japan in 1972, and is predominantly observed in women under the age of 30 year and in Asian populations. The pathogenesis is still poorly understood but is thought to include infections, and autoimmune and neoplastic diseases. The most common clinical manifestations are fever and painless cervical lymphadenitis. Diagnosis is based on the histopathological findings, characterized by focal necrosis in the paracortical region with abundant karyorrhexis, aggregates of atypical mononuclear cells around the zone of necrosis, absence of neutrophils and plasma cells, and usually intact lymph node capsule. There is no specific therapy for the condition, and aseptic meningitis can occur as one of the complications. Here, we report the case of a patient with Kikuchi-Fujimoto disease ac- companied with aseptic meningitis, which may be confused as a case of tuberculous meningitis and lymphadenitis. (Korean J Pediatr 2009;52:622-626)

A Case of CD30+ Nasal Natural Killer/T-Cell Lymphoma

Extranodal nasal natural killer (NK)/T-cell lymphoma is a very rare lymphoma characterized by strong association with Epstein-Barr virus infection, very aggressive clinical behavior, and poor prognosis. The typical phenotype of neoplastic natural killer cells in this entity is as follows: CD2+, CD56+, surface CD3-, cytoplasmic CD3epsilon+, and cytotoxic granule-associated protein positive. CD30 expression, a phenotype characteristic of anaplastic large-cell lymphomas, is not a typical feature of nasal NK/T-cell lymphomas. We describe the case of a 42-year-old woman with chronic nasal congestion and septal deviation who presented with progressive generalized tender erythematous plaques. A skin biopsy revealed an atypical angiocentric mononuclear cell infiltrate. Strong CD30 and CD3e immunoreactivities were noted in large atypical mononuclear cells within the infiltrate initially suggestive of a CD30+ T-cell lymphoma. However, flow cytometry of the skin lesion indicated that the cells were CD2+, CD4-, CD8-, and lacked surface CD3 more typical of a neoplasm of natural killer cells. Further studies revealed that the cells were CD56+, T-cell-restricted intracellular antigen-1+, and contained Epstein-Barr virus sequences consistent with a nasal-type NK/T-cell lymphoma. High titers of Epstein-Barr virus in the blood, evidence of sinonasal disease, and absence of a T-cell receptor gene rearrangement were additional features consistent with the diagnosis. The patient had a very aggressive clinical course and, despite combination chemotherapy, died 8 months after the onset of skin lesions. This case represents an example of nasal-type NK/T-cell lymphoma with expression of CD30. When presenting in the skin, the phenotypic and morphologic features of this lymphoma may lead to an erroneous diagnosis of a CD30+ large-T-cell lymphoma.

Leukemia cutis in a patient with acute monocytic leukemia presenting as unique facial erythema

A 67-year-old woman was referred to our department with a 1-month history of facial exanthemas. She had been diagnosed as having acute monocytic leukemia (French-American-British classification, M5b) based on the histological findings of bone marrow. Physical examination revealed diffuse edematous erythema on her cheeks, eyelids and glabella with scattered reddish papules. Histological examination demonstrated dense infiltration of atypical mononuclear cells in the dermis. Specific cutaneous lesions could occur in acute monocytic leukemia more frequently than in other types of leukemia, but rarely show symmetrical edematous erythema limited to the face.

Granulocytic sarcoma presenting as a thrombosed external hemorrhoid in a patient with myelodysplastic syndrome overt leukemia.

A 67-year-old Japanese man complained of a painful lump in his anus. He had a 15-month history of myelodysplastic syndrome (MDS) and had been diagnosed with MDS overt leukemia. A solid lump measuring 1.0 cm in diameter was detected in the anal verge. Under a diagnosis of a thrombosed external hemorrhoid, thrombectomy was performed under local anesthesia. One week after thrombectomy, the wound had not healed, and grayish-green tissue was seen at the bottom. A biopsy of the wound revealed atypical mononuclear cell infiltration. Myeloperoxidase and lysozyme were positive on immunohistochemical staining. Finally, the diagnosis of granulocytic sarcoma (GS) was made. Though it is well known that perianal complications occur quite often in patients with leukemia, it is unusual for a diagnosis of GS of the anus to be definitely established. To our knowledge, there has not been a previous report of GS presenting as a thrombosed external hemorrhoid. The development of GS should be considered during the management of such lesions, especially in patients with bone marrow disorders, such as acute myeloid leukemia (AML) or high-risk MDS.

Intracranial myeloid sarcoma

A 41-year-old female presented with a 2 d history of ‘refusing to talk’ and a 1 d history of ‘decreased movement’. She had a recent history of being treated for otitis media, but no history of malignancy. On admission, a full blood count and differential white cell count were normal. Magnetic resonance imaging revealed a 6 cm contrast-enhancing left-sided middle cranial fossa mass with extension inferiorly into the subtemporal fossa and parapharyngeal space (top left). The radiologist’s differential diagnosis included meningeal sarcoma, atypical meningioma, undifferentiated sinonasal cancer and lymphoma. A needle core biopsy was performed, but was nondiagnostic. Due to concerns about herniation and the lack of diagnostic tissue, the patient underwent a craniotomy. The cytospin and touch preparations from the tissue biopsy demonstrated a monomorphic population of atypical mononuclear cells with high nuclear:cytoplasmic ratios, vacuolated cytoplasm and prominent nucleoli (top right). Histological sections showed a diffuse infiltrate of large cells with large nuclei, irregular nuclear contours, prominent nucleoli and open chromatin (bottom left). The cells were positive for myeloperoxidase by immunohistochemistry. Flow cytometry detected myeloid blasts, which were CD34, CD13, CD33, CD117, CD20 and CD10. There was aberrant expression of CD19 and partial expression of CD56 (bottom right). Cytogenetic analysis demonstrated 45,X,-X, t(8;21;12)(q22;q22;q21). There was no evidence of bone marrow involvement by morphology or flow cytometry. The patient’s mental status improved dramatically after four cycles of cytarabine. She was lost to follow-up after 7 months. Myeloid sarcoma is an uncommon neoplasm and intracranial involvement comprises approximately 3% of all cases. Most are manifestations of previous or concurrent acute myeloid leukaemia although some may precede it. Intracranial myeloid sarcomas present as extra-axial masses and are believed to arise from the bone marrow of the skull. Histological differentiation between myeloid sarcoma and a large cell lymphoma can be difficult, if not impossible, without immunohistochemistry or flow cytometric analysis. Diagnosis can be especially problematic because these tumours can express B-cell antigens (e.g. CD19, CD79a), thus leading to the misdiagnosis of B-cell lymphoma.