Scedosporium apiospermum atrial mycetomas after lung transplantation for cystic fibrosis.

A 37-year-old patient with cystic fibrosis underwent double lung transplantation. She developed disseminated Scedosporium apiospermum infection 2 months after surgery. Along with multiple brain abscesses, lung infection, and chorioretinitis, a cardiac echo revealed 2 large intra-atrial mycetomas floating close to the right upper pulmonary vein orifice. The mycetomas were removed through a trans-atrial approach under cardiopulmonary by pass; histology and cultures confirmed the diagnosis. Despite intensive treatment, the patient succumbed from massive brain hemorrhage on the 10th postoperative day.

A woman with a solitary pulmonary nodule: is it a lung cancer?

BACKGROUND: Solitary pulmonary nodules present a real challenge for physicians. Due to the clinical implications and prognosis of a certain diagnosis, it should be pursued with any cost; a clear definition is not always simple and further investigations are often necessary to exclude the possibility of a malignancy. A diagnostic path must be followed and the clinical hypothesis should be reconsidered on the basis of the new information provided by the tests, always keeping in mind their limits! Sometimes only the surgical resection permits a definitive diagnosis. A 68 year-old non-smoker female with a pulmonary solitary nodule highly suspicious to be malignant at the chest CT, performed a FBS with BAL, negative for neoplastic cells and for infective agents, and a CT guided pulmonary biopsy that was inconclusive. The patient underwent then a video-thoracoscopic atypical lung resection that demonstrated the reactive nature of the lesion, definitely excluding the presence of a malignancy.

[Merkel cell carcinoma: an uncommon neuroendocrine cancer]. / Il carcinoma a cellule di Merkel: una rara neoplasia neuroendocrina.

Merkel cell carcinoma (MCC), firstly described by Torker in 1972, is an uncommon and aggressive neuroendocrine cancer of the skin. MCC tends to recur and precociously spread to lymph nodes. Five-year survival rate is between 35 and 75%. In literature there are not univocal criteria regarding the diagnosis and therapy of MCC, probably due to its rarity. Surgery plays an important role in the therapeutic strategy of this cancer. Surgical excision must be wide and guarantee at least 2-3 cm of free tumor margins. Sentinel lymph node biopsy is useful to identify those patients in which extensive lymph node dissection and/or adjuvant therapies (radio- and/or chemotherapy) are advisable. We hereby report a case of MCC of the left arm in a 48 year-old male. A wide excision was performed with sentinel lymph node biopsy that did not show any metastasis. Adjuvant radio therapy was administered. The patient was healthy at one year follow-up.

Hibernoma of the para-glottic space: an unusual tumour of the larynx.

Hibernoma is an unusual tumour of brown adipose tissue. Brown adipose tissue is common in mammalian hibernating animals and acts as a thermogenic organ. A first case of hibernoma was reported in 1906 by Merkel. This tumour usually arises in the back, shoulder region, mediastinum, retroperitoneum and in the neck. The neck location of hibernomas is rare and only 18 cases of cervical hibernoma have been reported in the English literature. A 48-year-old male with hoarseness and soft voice, present for 8 months, showed a lesion involving the anterior part of the right vocal fold, with no impaired mobility. This is the first case to be reported of laryngeal hibernoma located in a vocal fold, originating from the white fat tissue of the paraglottic space. Moreover, this report could be evidence of the development of hibernoma from white adipose tissue.

[A possible cause of misdiagnosis in tumors of the axilla: schwannoma of the brachial plexus]. / Una possibile causa di errore nella diagnosi differenziale delle formazioni ascellari: lo schwannoma asintomatico dei tronchi del plesso brachiale.

The Authors report a rare case of a 57 years old man affected by a left radial nerve schwannoma that occurred as an asymptomatic lesion of the axilla. At clinical examination the lump was undistinguishable from the most common axillary lymphadenopathy. A lymphoadenopathy was erroneously diagnosed with ultrasonography (US). This mistake was due to the low specificity of the instrumental methodology and to the rarity of an asymptomatic schwannoma of the infraclavicular brachial plexus. The neoplasia was excised without using the microscope. In the early post-operative follow up, a "falling" attitude of the wrist, the hand and the fingers appeared, peculiar for a lesion of the radial nerve. Furthermore a hypoaesthesia of the skin of first finger and of the first interosseus space was associated. The sensitive and motor electromyography showed a radial nerve suffering. The "stupor" of the nerve trunk was treated with steroid therapy for 7 days and the patient underwent to some series of neuro-rehabilitative physical therapy for 12 weeks. The postoperative total body CT, showed that the lesion was unique: therefore it was possible to exclude the diagnosis of neurofibromatosis. After 28 months electromyography and axillary US were performed showing the complete resolution of the motor and sensitive deficit and the absence of local recurrence.

Malignancies following lung transplantation.

During the last 2 decades, long-term survival after lung transplantation has significantly improved. However, among the complications related to the continuous administration of immunosuppressive drugs, malignancy plays an important role. We retrospectively revisited our series of patients to report our experience. From January 1991 we performed 134 lung transplantations in 128 recipients (mean age, 33.4 +/- 13.5 years). In all patients the first-line immunosuppressive regimen was based on a calcineurin inhibitor (cyclosporine or tacrolimus), an antimetabolic agent (azathioprine), and steroids. Five patients (4.2%) developed malignancy and the mean time of occurrence after the transplantation was 46.4+/-23 months. The mean age was 41 +/- 16 years (P = not significant [ns]). The tumors were as follows: laryngeal cancer (radiotherapy), colon cancer (surgery plus adjuvant chemotherapy), gastric cancer (surgery plus adjuvant chemotherapy), endobronchial non-Hodgkin lymphoma (NHL) (endoscopic resection plus chemoradiotherapy), and cutaneous and visceral Kaposi's sarcoma (KS) (chemotherapy). All patients have reduced the dose of immunosuppressive drugs; in 1 of them, tacrolimus was changed to rapamycin. Two patients died because of neoplastic dissemination, another 1 due to obliterans bronchiolitis. The 2 patients with NHL and KS are alive at 6 and 9 months, respectively, without signs of recurrence. Malignancies after lung transplantation represent an important problem. A multidisciplinary approach is mandatory to obtain satisfactory results in terms of improved quality of life and long-term survival.

Preoperative anaemia does not affect the early postoperative outcome in patients with lung cancer.

AIM: Several prognostic factors like age, gender, histology, stage, type of operation, associated disorders and administration of induction therapy have been evaluated to assess the risk of postoperative complications and outcome in patients with resectable lung cancer. Anemia is a frequent condition in this subset of patients being estimated up to 50%. The aim of this retrospective study was to evaluate the effect of preoperative anemia on early outcome after lung cancer resection. METHODS: One-hundred thirty nine consecutive patients undergoing surgery for non small cell lung cancer were retrospectively considered. The mean age was 64.8+/-11.6 years. No patient received blood transfusions or administration of erythropoetin preoperatively. Overall, we performed 96 lobectomies, 14 pneumonectomies, 2 bilobectomies and 27 atypical resections. A subset of 27 patients (19.4%) (group I) had a preoperative value of Hb less than 12 g/dl (10.4+/-1.9 g/dL). Seven patients of them were stage IA (26%), 9 stage IB (33.3%), 2 stage IIA (7.4%), 6 stage IIB (22.2%), 2 stage IIIA (7.4%) and 1 stage IIIB (3.7%). Age, gender, stage, type of operation, induction chemotherapy, comorbidities were evaluated by univariate analysis comparing patients with and without preoperative anaemia. The two groups were homogenous regarding demographic characteristics. RESULTS: Three patients (11.1%) in group I and 2 (1.8%) in group II required blood transfusions after surgery (P=0.01); 4 of them received pneumonectomy (P<0.0001). The overall morbidity was 17.9% (25/139); the most frequent complication was persistent air leakage, followed by retention of secretions. No statistically significant difference was observed between the 2 groups about early mortality (1 patient-3.7% in group I and 2 patients-1.8% in group II) and postoperative complications (5 patients-18.5% in group I and 20 patients-17.9% in group II). CONCLUSION: Preoperative anaemia is not a risk factor for an increased rate of postoperative complications and should not be considered a contraindication to surgery.

Evidence for local and systemic activation of immune cells by peritumoral injections of interleukin 2 in patients with advanced squamous cell carcinoma of the head and neck.

Interleukin 2 (IL2) was injected peritumorally and intranodally in 36 patients with unresectable squamous cell carcinoma of the head and neck enrolled in an Eastern Cooperative Oncology Group-sponsored phase Ib trial (EST P-Z388). Groups of 6 patients received escalating doses(200, 2 x 10(3), 2 x 10(4), 2 x 10(5), 2 x 10(6), and 4 x 10(6) units) of IL2 daily 5 times/week for 2 weeks. Tumor biopsies were obtained before and after IL2 therapy. Tumor tissue was provided for histology, and the remaining fresh tissue was divided for snap-freezing in -75 degrees C and for separation of tumor-infiltrating lymphocytes (TIL) and tumor cells. Immunophenotyping of TIL performed on cryostat sections of paired pre- and post-IL2 biopsy tissues showed increases after IL2 therapy in the number of T-cells (P = 0.005), natural killer (NK; CD16+) cells (P = 0.0001), CD25+ cells (P = 0.004), and HLA-DR+ cells (P = 0.001) accumulating in the tumor stroma. In the tumor parenchyma, NK cells (P = 0.0001) and HLA-DR+ cells (P = 0.003) were increased after IL2 therapy. The T:NK cell ratios in the tumor stroma and parenchyma were decreased after therapy, suggesting selective accumulation of NK cells. By flow cytometry, TIL recovered from post-IL2 biopsy tissues were enriched (P < 0.05) in CD3-CD56+ (NK) cells. In situ hybridization with [35S] cDNA probes for cytokines and IL2 receptors indicated that the numbers of cells expressing mRNA for IL2, tumor necrosis factor alpha, IL1-beta, gamma-interferon, transforming growth factor beta, and IL2 receptor p55 or p70 were increased in post-IL2 biopsy tissues as compared to pre-IL2 tissues. Cytolytic activity of TIL isolated from post-IL2 tissues was also increased, as determined in 4-h 51Cr release assays against K562 targets (12 +/- 3 mean lytic units/10(7) cells +/- SEM pre-IL2 versus 46 +/- 13 post-IL2; n = 16) and against autologous tumor (13 +/- 8 versus 68 +/- 26; n = 9). Fresh TIL of one clinical responder showed relatively high levels (195 lytic units) of autotumor cytotoxicity after IL2 therapy versus no activity prior to therapy. In the blood, NK and lymphokine-activated killer cell activity, and percentages of CD3-CD56+ NK cells and of activated (CD25+) T-lymphocytes were increased for all doses of IL2.(ABSTRACT TRUNCATED AT 400 WORDS)

Immunologic effector cells in head and neck cancer.

Freshly isolated tumor-infiltrating lymphocytes (TIL) and lymph node lymphocytes (LNL) in patients with head and neck cancer (HNC) often have low or undetectable functional responses. Because impaired ability of these cells to produce cytokines could be responsible for their functional incompetence, spontaneous and in vitro-induced production of interleukin-2 (IL2), interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), and interferon gamma (IFN-gamma) by TIL, LNL from tumor-free as well as tumor-involved lymph nodes (LN), and peripheral blood lymphocytes (PBL) were measured. Although TIL or PBL of patients with HNC produced IL-1 beta and TNF-alpha spontaneously or after in vitro activation, LNL did not produce measurable levels of these cytokines. LNL also produced lower levels of IFN-gamma than PBL. In situ hybridization for cytokine mRNA performed with tumor tissues, and LN of patients with HNC showed that TIL as well as LNL localized in the immediate proximity of the tumor were activated, as evidenced by the expression of mRNA for IL2, IFN-gamma, IL-1 beta, TNF-alpha, and both alpha- and beta-chains of the IL2 receptor. In addition, many LNL located next to the tumor expressed mRNA for transforming growth factor-beta (TGF-beta). In contrast, LNL not adjacent to the tumor in involved LN, as well as those in tumor-uninvolved LN, did not express mRNA for cytokines or IL2 receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

In situ hybridisation for cytokine gene transcripts in the solid tumour microenvironment.

To determine if mononuclear cells (MNC) infiltrating various types of human solid tumours express genes for cytokines, in situ hybridisation with 35S-labelled cDNA antisense probes for interleukin 2 (IL2), interferon gamma (IFN-gamma), tumour necrosis factor alpha (TNF-alpha), interleukin 1-beta (IL1-beta), transforming growth factor beta (TGF-beta) and interleukin 2-receptors (IL2R) was performed. Fresh-frozen tissue samples of ovarian carcinomas (n = 13), breast carcinomas (n = 12), and squamous cell carcinomas of the head and neck (SCCHN, n = 7) were evaluated for the presence and localization in the tumour of MNC positive for cytokine genes. In ovarian tumours and those breast carcinomas producing little or no mucin, only rare positive MNC were observed. In contrast, breast carcinomas producing mucin and all SCCHN contained numerous MNC expressing gene transcripts for IL2, IFN-gamma, TNF-alpha, IL2R as well as TGF-beta. In tumour-involved lymph nodes of patients with SCCHN, MNC expressing genes for cytokines were found around tumour metastases but not in non-involved areas. These data suggest that tumours expressing immunogenic antigens (e.g. mucin) contain many activated MNC, while other tumours either fail to activate or suppress functions of infiltrating MNC. In SCCHN or tumour-draining lymph nodes, local down-regulation of antitumour responses might be mediated by TGF-beta produced by activated tumour-infiltrating MNC.

Human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) antigens and genome in lymph nodes of HIV-positive patients affected by persistent generalized lymphadenopathy (PGL).

The presence of human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) antigens and genome has been investigated in 50 lymph nodes involved by persistent generalized lymphadenopathy (PGL). All the patients were HIV infected and most of them (42 of 50) also had anti-EBV serum antibodies. At lymph node level, HIV and EBV antigens were studied by immunohistochemistry using monoclonal antibodies directed against viral core proteins. The HIV p24 protein was detected in 43 of 50 lymph nodes within the B-cell germinal centers with a reticular pattern. Few cells with positive results for EBV antigens were found in only 2 of 50 lymph nodes. These rare EBV-positive centrocyte-like cells were mainly located in the germinal centers. The presence of HIV and EBV genome was also studied in lymph nodes involved by PGL, with the use of in situ and Southern blot hybridization. A positive reaction for HIV genome was detected in only 1 of 14 lymph nodes with the Southern blot hybridization, and the presence of EBV genome was never demonstrated in these lymph nodes with the use of both in situ and Southern blot hybridization. The expression of EBV antigens and genome was also investigated in the peripheral blood of 15 patients with PGL in which cells with positive results for EBV antigens were detected in a single case with a frequency of 1 X 10(-4). No evidence of EBV genome was found with the use of the in situ hybridization. These results suggest that EBV is not present in lymph nodes during the PGL phase and that its possible implication in the pathogenesis of acquired immune deficiency syndrome (AIDS)-associated lymphoma might be a late event.

Management of abdominal lymphoproliferative diseases in the era of laparoscopy.

BACKGROUND: The treatment of lymphoproliferative diseases requires extensive histological, immunohistochemical, and cytogenetic diagnosis. The aim of this study was to analyze the results of 66 laparoscopic procedures in the diagnosis, staging, and restaging of hematological malignancies localized in the abdominal cavity. METHODS: Between July 1993 and March 1998, 64 consecutive patients (28 male and 36 female; mean age 46.6 years, range 7 to 69) with diagnosed or suspected lymphoproliferative diseases were referred for primary diagnosis or reassessment and for staging/restaging. RESULTS: Sixty-two out of 66 procedures (93.9%) were completed laparoscopically. CONCLUSIONS: The minimally invasive approach, in the management of lymphoproliferative diseases, is able not only to provide an adequate specimen for proper diagnostic techniques, but also, when compared with open surgery, to offer a large number of advantages.

Detection of TT virus in lymph node biopsies of B-cell lymphoma and Hodgkin's disease, and its association with EBV infection.

Human TT virus (TTV) recently isolated from the serum of a patient with post-transfusion hepatitis does seem to have only hepatopathic effect. The virus can also infect the serum, peripheral blood mononuclear cells (PBMC) and bone marrow cells (BMC ). Additional evidence has indicated that TTV is also present in the serum of people with hematopoietic malignancies. A significant increase in the incidence of lymphoma has recently been observed worldwide. We have investigated the presence of TTV DNA in lymph node biopsies of Italian patients affected with the most common lymphoma types in Western Countries: follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL) and nodular sclerosis Hodgkin's disease (NS-HD). The possible role of a co-infection with Epstein-Barr virus (EBV) has also been investigated. DNA was extracted from 73 paraffin-embedded and 38 snap-frozen tissue specimens. From these, only 67 samples (29 paraffin-embedded and 38 snap-frozen tissues) from a total of 56 patients, were suitable for PCR analysis. TTV and EBV were detected by PCR using primers from two different conserved region in TTV and EBV genomes respectively. TTV DNA was detected in 30.0-50.0% of FL, 30.8% of DLBCL and 30.0-50.0% of NS-HD cases, depending on the primers used. All cases of non-specific reactive lymphoid hyperplasia (RLH), used as a putative control, were negative. The two major TTV genotypes circulating in Italy (G1 and G2) were detected in the analysed lymphoid neoplasms. EBV DNA was detected in 40.0% of FL, in 72.7%of DLBCL, in 80.0% of SN-HD and in 40.0% of RLH cases. EBV co-infection was found in 90% of TTV positive cases. The in situ hybridization assay was performed in TTV positive frozen samples. The significant prevalence of TTV DNA in lymphocytes circulating in the lymph nodes of both B-cell lymphomas and HD reported herewith suggests an implication of TTV infection in the development of these lymphoproliferative disorders.

Salvage resection after previous laryngeal surgery: total laryngectomy with en bloc resection of the overlying cervical skin.

OBJECTIVE: To evaluate the effectiveness of extended total laryngectomy for the treatment of recurrences of laryngeal cancer. DESIGN: We conducted a retrospective clinical study of patients who had undergone extended total laryngectomy and were seen over a 15-year period. The follow-up period ranged from 3 to 15 years. SETTING: Academic tertiary referral medical center. PATIENTS: We observed 15 patients who were affected by a recurrence of laryngeal cancer that extended to the overlying soft tissue. All patients were male. The mean age was 61.5 years. Thirteen patients had previously undergone partial laryngeal surgery, and 2 patients had undergone radiation therapy, without success. INTERVENTION: All patients underwent total laryngectomy extending to the soft tissue, including the overlying skin. RESULTS: Five of the 15 patients died of local recurrence, and 1 patient died of massive postoperative hemorrhaging. An actuarial survival rate of 60% was observed at 5 years. CONCLUSION: Total laryngectomy extending to the soft tissues seems to be an effective procedure for treating local recurrences of laryngeal cancer after partial laryngectomy or failure of radiation therapy.

Adhesion molecules and lymphocyte recruitment in lymphocytic thyroiditis, thyroid papillary carcinoma and parotid adenolymphoma.

Lymphocytic infiltrates are usually present in chronic lymphocytic thyroiditis, thyroid papillary carcinoma and parotid adenolymphoma. We selected these conditions to investigate the mechanisms of recruitment and organization of lymphocytic infiltrates in extranodal tissues. MoAbs in immunoperoxidase were used to identify the expression of ICAM-1 and VCAM-1 on endothelial cells (EC), and of their ligands LFA-1 and VLA-4 on lymphocytes and accessory cells. VCAM-1 positive EC were rarely observed in thyroids devoid of lymphocyte infiltration. Conversely, EC in chronic lymphocytic thyroiditis and in papillary carcinoma showed positive immunostaining for VCAM-1 and ICAM-1. These findings were associated with the presence of lymphocytes positive for the ligands VLA-4 and LFA-1. The upregulated expression of VCAM-1 on perifollicular capillaries was co-distributed with an accumulation of VLA-4 positive lymphocytes. In adenolymphoma, all EC were ICAM-1 positive, whereas the majority of vessels were VCAM-1 negative. Consequently the majority of lymphoid cells were LFA-1 positive and VLA-4 negative. We suggest that ICAM-1 and VCAM-1 expression on EC play a role in the recruitment of lymphocyte infiltration in chronic lymphocytic thyroiditis and papillary carcinoma. Furthermore, the upregulation of VCAM-1 and VLA-4 in thyroid reactive and neoplastic conditions may be linked to an immune response possibly related to thyroid tissue antigens.

Peripheral T cell lymphoma in adults: morphological and phenotypical study of four cases.

In the present study we investigated the lymph node morphology and distribution of cell surface phenotypes in four cases of adult peripheral T cell lymphoma. Histologically, the tumors were classified as T zone lymphoma, T cell lymphoma with large multilobated nuclei and T cell immunoblastic sarcoma. In the T zone lymphoma the neoplastic lymphocytes were E+ (90%) and exhibited intensive focal staining for acid phosphatase (93%) and acid esterase (92%); the phenotype distribution revealed low expression of the T-3 antigen (49%), selective expression of the T-4 antigen (72%) and poor expression of T-6 (10%) and T-10 antigens (22%). Some of these features are present in normal and in neoplastic immature T cells. In the remaining three cases the majority of lymph node cells were E+ (59-75%), T-3+ (67-80%) and T-8+ (43-55%). A distinctive feature of the T cell immunoblastic sarcoma was the presence of high percentages of DR+ cells (62%; 63%). Thus our results indicate that the morphological heterogeneity of peripheral T cell lymphoma is also paralleled by a variety of surface phenotypes and that phenotype studies may provide a useful contribution to identification and accurate classification of peripheral T cell neoplasms.

A clinical radiographic and histologic revaluation of a 10 years sample of surgically treated cysts of the jaws, with special emphasis on keratocysts.

AIM: The aim of this study was to compare the histologic features of the cysts as regards their radiographic and clinical aspects, in order to assess the accuracy of the diagnosis, the appropriateness of the treatment and the reliability of the follow-up. METHODS: A sample of 173 cysts of the jaws was reviewed in accordance with the 1992 WHO histological classification. RESULTS: Of these cysts, 77.44% were inflammatory, 12.71% follicular and 8.67% keratocysts. The cysts were slightly more frequently located in the mandible (52.60%) than in the maxilla (47.39%) and they affected men more frequently (60.11%) than women (39.88%). However keratocysts and nasopalatine cysts were twice as frequent in women than in men. No recurrence of keratocysts was found, either in those correctly diagnosed at the moment of the first histologic examination, or in those firstly erroneously diagnosed as an other type of cysts. CONCLUSION: On the basis of the fairly high percentage of non-inflammatory cysts in adult patients, it can be suggested to perform an orthopantomography as a preventive measure, every 5 years, particularly when impaired teeth are present.

Double localization of keratoacantho-ma on the cutaneous and mucosal sides of the lower lip: report of a case.

The clinical course and histological features of keratoacanthoma (KA) are well recognized by dermatologists and pathologists, but they are less familiar to dental professionals. The aims of this report were to describe an unusual case of simultaneous intraoral and labial KA and to identify the most important aspects of the clinical management of this lesion.

Breast tuberculosis: rare but still present in Italy--a case of mycobacterium breast infection.

Breast tuberculosis is a rare disease in highly endemic countries, and it is even rarer in Western countries, where only occasionally the local population is affected. The rarity of the disease and particularly the lack of a typical clinical-radiological presentation may cause tuberculosis to be mistaken for breast cancer or a pyogenic abscess. The authors present a case of breast tuberculosis in a 27-year-old nulliparous woman, an Italian citizen of the Caucasian race, who has never resided in a tuberculosis endemic area. She presented with painful retroareolar and para-areolar swelling in the right breast associated with cutaneous hyperemia (without fistulization), resistant to antibiotic therapy. Histopathological examination revealed features of mastitis with epithelioid histiocytes and Langhans giant cells and was characterized by the presence of caseous necrosis which suggested tuberculous inflammation. Ziehl-Neelsen staining showed the presence of acid fast bacilli. In countries where tuberculosis is non-endemic, breast tuberculosis should always be included in the differential diagnosis in cases of inflammatory breast lesions resistant to the usual antibiotic therapies. Early recognition may prevent both clinical progression and surgical excision, as breast tuberculosis usually regresses as a response to appropriate anti-tuberculosis therapy.

Immunohistopathogenesis of persistent generalized lymphadenopathy in HIV-positive patients.

Persistent generalized lymphadenopathy (PGL) is a reactive lymphadenitis affecting HIV-positive patients; furthermore, PGL is often a prodrome of AIDS-related complex and AIDS. In the present review the authors describe the histology and the immunohistochemistry of lymph nodes of patients affected by PGL. Histologic alterations of lymph nodes with PGL are classified according to three main types: follicular hyperplasia without or with follicular fragmentation, follicular involution and follicular depletion. Immunohistology demonstrates a peculiar infiltration of CD3+/CD4+ and CD3+/CD8+ lymphocytes in germinal centers; CD3+/CD8+ are often grouped in small clusters centered by a newly formed small blood vessel. Accessory follicular dendritic reticulum cells (FDRCs) of germinal centers are characterized by a positive staining for p24 and p19 HIV major core antigens. In germinal centers, FDRCs undergo progressive lysis in follicular involution and in follicular depletion. Other viral antigens, such as EBV, are infrequently seen in lymph nodes from HIV-positive patients. Paracortical areas of lymph nodes are often characterized by prominent postcapillary venule proliferations and by hyperplasia of the endothelial cells which are HLA-DR positive, often p19 and p24 positive, and occasionally express HIV genome. In conclusion, in PGL the histologic changes correlate well with the immunohistologic features; accordingly, PGL might be considered the result of abnormal immune reactions to several stimuli still incompletely known.