Spindle cell tumors associated with mycobacteria in lymph nodes of HIV-positive patients: 'Kaposi sarcoma with mycobacteria' and 'mycobacterial pseudotumor'

Mycobacterial Spindle Cell Pseudotumor of the Nasal Cavity

BACKGROUND

Mycobacterial spindle cell pseudotumor (MSCP) represents an uncommon tumor-like proliferation associated with nontuberculous mycobacterial infection, i.e., M. avium intracellulare, affecting primarily the lymph nodes of immunocompromised men in their 5th decade. Involvement of the nasal cavity by MSCP is exceedingly rare with only 3 well-documented examples in the literature.

METHODS

A 74-year-old, HIV-negative, man presented with a 0.5-cm nodule of the left nasal cavity clinically presenting as a "nasal polyp." His medical history was significant for colonic adenocarcinoma, cutaneous basal cell carcinoma, and chronic lymphocytic leukemia (CLL) transforming to B-cell prolymphocytic leukemia, responsive to chemotherapy. The patient was diagnosed with prostatic adenocarcinoma treated with radiotherapy two months before the nasal lesion was detected. No lymph node enlargement, pulmonary involvement or hepatosplenomegaly were noticed. The nasal nodule was surgically excised and histopathologically examined to rule out metastatic disease or CLL relapse.

RESULTS

Microscopically, the lesion comprised a well-circumscribed, monotonous, spindle cell population in a vaguely storiform arrangement mixed with a heavy infiltrate of neutrophils and sparse lymphocytes. The spindle cells featured finely granular rich eosinophilic cytoplasm with rounded, oval to epithelioid, or elongated nuclei with vesicular chromatin and one or two distinct nucleoli. The lesional cells lacked overt cytologic atypia and showed occasional regular mitoses. The surface epithelium was intact or focally ulcerated. By immunohistochemistry, the spindle cell population stained strongly and diffusely for CD68 and was negative for AE1/AE3, SMA, CD34, and PSA. CD3 highlighted scattered lymphocytes. Ziehl-Neelsen stain disclosed numerous intracytoplasmic acid-fast bacilli. A diagnosis of MSCP was rendered. No recurrences were observed during a 24-month follow-up period.

CONCLUSION

Although exceptionally rare, MSCP should be considered in the differential diagnosis of nodular lesions of the nasal cavity that are characterized microscopically by marked spindle cell proliferation in a vague storiform pattern, admixed with a lymphocytic or mixed inflammatory infiltrate. A negative medical history for HIV infection and medication-induced immunosuppression should not preclude a diagnosis of MSCP, particularly in extranodal sites. Once the diagnosis is established, prognosis appears to be excellent for nasal MSCP following conservative surgical excision.

Unusual Presentations of Mycobacterium Tuberculosis in HIV-Positive Patients: A Case Series

Necrotizing and non-necrotizing epithelioid granulomatous chronic inflammation is the usual recognizable histopathologic presentation of mycobacterial infections. In immunosuppressed patients, atypical histomorphologic patterns may occur. Rare and diagnostically challenging manifestations of nontubercular mycobacterial infections in transplant and Human Immunodeficiency Virus (HIV)-infected patients include mycobacterial spindle cell pseudotumor and suppurative lesions. Lesions composed of nodular spindle cell proliferation mimicking inflammatory, histiocytoid and spindle cell tumors, and similarly suppurative lesions simulating abscesses have been mostly reported in association with nontuberculous mycobacterial infections mainly in nodal and various extranodal sites. Similar lesions related to Mycobacterium tuberculosis that involve serosal membranes are unusual and diagnostically challenging. Our aim is to report mycobacterial spindle cell pseudotumor-associated pericarditis, suppurative abscess-forming pleuritis, and cholesterol pleuritis due to tuberculosis in three HIV-infected young adult males. Initially, we confused the mycobacterial spindle cell pseudotumor for Kaposi sarcoma, the suppurative pleuritis for bacterial and fungal empyema, and the cholesterol pleuritis with rheumatoid arthritis. A prior knowledge of the immune status of our patients helped us confirm our final correct diagnosis of mycobacterial infection by performing Ziehl-Neelsen special stain. Polymerase chain reaction detected Mycobacterium tuberculosis in respiratory samples. Utilization of acid-fast special stains in all HIV-patients regardless of the histopathologic appearances, and the application of an appropriate panel of immunomarkers should help pathologists reach the correct diagnosis and avoid pitfalls. Without prior clinical knowledge, pathologists should raise this possibility in young patients with such unusual manifestations, because correct pathologic recognition is clinically important for the appropriate management of these vulnerable patients.

Diagnosis of cutaneous mycobacterial spindle cell pseudotumor in the absence of typical inflammatory cells: A case report

Mycobacterial spindle cell pseudotumor (MSP) is a non-neoplastic condition that is characterized by spindle-shaped histiocytes colonized by mycobacteria. MSP is most commonly diagnosed in the immunocompromised and, while MSP can occur throughout the body, the most common sites of MSP involvement are the lymph nodes and the skin. To diagnose MSP, histopathological analysis typically demonstrates the presence of inflammatory cells, in addition to spindle cells and the unequivocal mycobacteria, which guides the diagnosis away from potential neoplasms. If properly diagnosed and treated with appropriate antibiotic therapy, patients tend to experience almost complete resolution of their symptoms. MSP is a rare condition; to our knowledge, there have only been 11 documented cases of cutaneous MSP, including the one introduced in this report. Here, we present a unique case of a 50-year-old female on chronic immunosuppressive therapy diagnosed with cutaneous MSP in the absence of inflammatory cells on pathology.

Abdominal wall mycobacterial spindle cell pseudotumor lesion

Mycobacterial spindle cell pseudotumor is a rare entity that is histologically characterized by spindle-shaped histiocytes with acid-fast bacilli. It is primarily reported in immunocompromised patient in various body sites. We present a case of mycobacterial spindle cell pseudotumor in an abdominal wall mass from an immunosuppressed patient and discuss the characteristic findings.

Mycobacterial spindle cell pseudotumor in a woman with HIV

Mycobacterial spindle cell pseudotumor (MSP) is a rare benign entity characterized by tumor-like proliferations of spindle-shaped histiocytes containing acid-fast positive mycobacteria. MSPs tend to occur predominantly in immunocompromised individuals and are concerning for a malignant neoplasm. We report a case of MSP occurring in a woman with human immunodeficiency virus and a tumor-like mass in the abdomen. A subsequent biopsy revealed MSP, which was successfully treated with antimycobacterial therapy.

Pulmonary Mycobacterium Spindle Cell Pseudotumor in Patient With Liver Transplant

We report a case of liver transplant patient who presented with lung masses, found to be Mycobacterium spindle cell pseudotumors. The masses demonstrated hypermetabolic activities on positron emission tomography. Core biopsy revealed sheets of spindle histiocytic cells with abundant acid-fast bacilli identified as Mycobacterium avium-intracellulare complex. This finding is a rare presentation of Mycobacterium infection, mainly nontuberculous Mycobaterium. It is characterized by a benign, spindle cell mass-forming reaction. Most of the reported cases had acquired immune deficiency syndrome or organ transplant. Histopathology illustrating the proliferation of spindle cell shaped histiocytes containing numerous acid-fast bacilli is the gold standard for diagnosis. The standard treatment has not been well established; previously reported cases followed the standard treatment for Mycobacterium based on organ involvement. Our case is the first case to our knowledge that reports pulmonary Mycobacterium spindle cell pseudotumors in a liver transplant recipient.

Mycobacterium Spindle Cell Pseudotumor Caused by Mycobacterium xenopi: A First Described Association of a Rare Entity Presenting in the Lung

Mycobacterial spindle cell pseudotumor (MSP) is a rare benign lesion characterized by a proliferation of bland spindle-shaped histiocytes with vague granulomatous formation, positive for acid-fast bacilli staining. This lesion is usually reported in the lymph nodes and skin of immunocompromised patients; only 6 cases primary in the lung have been reported in the English literature to this date. In this article, we present the case of a 42-year-old female status post failed kidney-pancreas transplant with subsequent multiple kidney transplants, on chronic immunosuppression, who developed a mass in the left lower lobe consistent with MSP. Mycobacterium xenopi was identified in lung tissue culture, an association never previously described in literature. This case report alerts for the possible association of this rare form of non-tuberculous mycobacteria in the pathogenesis of MSP and highlights the importance of this differential diagnosis in lung masses of immunocompromised patients.

Laryngeal Inflammatory Pseudotumour Secondary to Mycobacterium kansasii

BACKGROUND

Inflammatory pseudotumours (IPT) are rare benign tumours characterised by spindle-shaped histiocyte proliferation often mimicking a soft tissue sarcoma. They can occur in different parts of the body and various aetiological factors have been proposed. To our knowledge this is the first case report of IPT of the larynx caused by mycobacterial disease.

CASE REPORT

We report a case of IPT of the larynx in an immunocompromised 81-year-old lady presenting with stridor and dysphagia with known disseminated Mycobacterium kansasii of the lungs.

CONCLUSION

This case demonstrates both the clinical and histological difficulties in making the diagnosis of IPT. A high index of suspicion is needed, and the importance of a multidisciplinary approach in the work-up, diagnosis, and management is highlighted.

Pulmonary Mycobacterial Spindle Cell Pseudotumor: A Report of 3 Cases Including a Practical Approach to Histopathologic Recognition of This Unusual Entity

Mycobacterial spindle cell pseudotumor (MSP) is a rare benign spindle cell lesion containing acid-fact mycobacteria. These lesions are most commonly identified in the lymph nodes, skin, spleen, or bone marrow of immunocompromised patients and only rarely involve the lungs. We report 3 cases of pulmonary MSP, which include 2 patients who are known to be HIV-positive. The histopathological diagnosis of MSP in the lung lends itself to many challenges due to its rare incidence and its spindled tumor-like appearance. The differential diagnosis is broad and includes both benign and malignant entities. We highlight the importance of the clinical context in which these lesions typically present and the morphologic spectrum of features seen, and we offer a practical approach to the workup of pulmonary mycobacterial pseudotumor. Appropriate recognition of this entity should lead to an accurate diagnosis of a treatable benign condition despite the clinical presentation often favoring malignancy.

Mycobacterial spindle cell pseudotumour: epidemiology and clinical outcomes

INTRODUCTION

Mycobacterial spindle cell pseudotumour (MSP) is a rare disease characterised by tumour-like local proliferation of spindle-shaped histiocytes containing acid-fast positive mycobacteria. The aim of this literature review is to describe the clinical parameters and treatment outcomes of patients with MSP.

METHODS

A literature search was conducted using the search terms related to mycobacteria and spindle cell tumours. A previously unreported stem cell transplant recipient from our institution diagnosed with MSP was also included. Demographics, comorbidities, site of infection, treatment and clinical outcomes were analysed.

RESULTS

Fifty-one patients were analysed. Twenty-six (51%) had HIV infection. Mycobacterium avium complex was the most frequent organism isolated in 24 (47.1%) followed by Mycobacterium tuberculosis complex in eight (16%) cases. Lymph nodes were the most common site of infection (45.1%). Twenty (39.2%) patients received antimycobacterial agents, 12 (23.5%) underwent surgical resection and six (11.8%) received antimycobacterial agents plus surgery. Treatment was successful in 24 (47.1%) patients and failed in 15 (29.4%); 13 of these 15 patients died. Antimycobacterial therapy was significantly associated with successful outcome compared with surgical resection or no treatment (P<0.001).

CONCLUSION

MSP is a rare condition associated primarily with immunodeficiencies. Antimycobacterial therapy is significantly associated with successful outcome.

Iatrogenic solid tumors following immunosuppressive therapy

Immunosuppression induced by chronic medication, such as occurs post-transplantation, may increase a patient's risk of developing solid tumors. These are often rare tumors characterized by odd presentations. This review focuses on commonly encountered iatrogenic, non-hematopoietic solid tumors following immunotherapy and provides a practical approach to their diagnosis. All of the malignancies covered in this review are viral-induced. They include human papillomavirus (HPV)-associated carcinomas, Epstein-Barr virus (EBV)-associated tumors, Merkel cell polyomavirus (MCPyV)-related Merkel cell carcinoma, and Human Herpesvirus 8 (HHV8)-related Kaposi sarcoma. The complementary diagnostic role of ancillary studies, such as immunohistochemistry and in-situ hybridization that target these oncogenic viruses, is addressed.

Histopathology of Spindle Cell Vascular Tumors

Vascular tumors with a spindled morphology represent a diagnostic challenge in soft tissue pathology. It may be difficult to distinguish certain benign entities in this category from spindled vascular tumors of intermediate malignancy or even spindled variants of angiosarcoma. This article focuses on vascular tumors characterized by a predominantly spindled morphology, including spindle cell hemangioma, acquired tufted angioma (angioblastoma of Nakagawa), kaposiform hemangioendothelioma, Kaposi sarcoma, and spindle cell variants of angiosarcoma.

Surgical Pathologic Diagnosis

Surgical pathology results can play a crucial role in the management of immunocompromised patients. Here we highlight factors that differ between immunocompromised and immunocompetent hosts, such as variation in inflammatory response. Conditions that are covered include drug reactions, disease within solid organ allografts, immune reconstitution inflammatory syndrome, specific immunodeficiency syndromes, neoplasms related to viral infections, and viral, bacterial, fungal, and parasitic infections. Special techniques including immunohistochemistry, in situ hybridization and molecular detection of pathogen nucleic acid from formalin-fixed, paraffin-embedded tissue are discussed.

Mycobacterial spindle cell pseudotumour of the brain in a patient with sarcoidosis

Mycobacterial spindle cell pseudotumours (MSP) are benign lesions characterised by local proliferation of spindle-shaped histiocytes caused by mycobacterial infections. Cerebral MSP due to Mycobacterium avium intracellulare (MAI) infection is rare, and is often misdiagnosed clinically and radiologically as a brain tumour. We present a case with underlying sarcoidosis and known pulmonary MAI infection presenting with partial seizures and headaches. Imaging of the brain revealed a solitary extra axial tumour within the right temporal area. Biopsy of the tumour showed evidence of MPS due to MAI infection. Prolonged treatment with antituberculous therapy showed complete resolution of the cerebral lesion.

Pulmonary mycobacterial spindle cell pseudotumor in a lung transplant patient: progression without therapy and response to therapy

Mycobacterial spindle cell pseudotumor (MSP) represents a rare, non-malignant, mass-forming reaction to various mycobacterial infections, typically occurring in immunocompromised patients. It is characterized by the proliferation of spindle-shaped fibrohistiocytic cells without the formation of epithelioid granulomas. Without staining for acid-fast bacilli, histological distinction from other spindle cell lesions, including malignancy, can be difficult. Most of the MSP cases reported in the literature have involved lymph nodes, skin, spleen, or bone marrow, but rarely involve the lung. MSP predominately occurs in patients who are immunosuppressed. We present a patient with MSP of the transplanted lung caused by non-tuberculous mycobacteria, in whom both the natural course of the untreated pseudotumor as well as the response to antimycobacterial treatments were observed.

Nontuberculous mycobacteria-associated spindle cell pseudotumor of the nasal cavity: a case report

Mycobacterial spindle cell pseudotumor (MSP) is a rare mass-forming lesion caused by mycobacterial infection, mostly in immunocompromised patients. Since it is composed of a proliferation of spindle-shaped fibrohistiocytic cells without forming epithelioid cell granulomas, histological distinction from other spindle cell lesions is often difficult and its pathophysiology is poorly understood. MSP arising in the nasal cavity is extremely rare, and only two cases have been reported previously. Here we report a case of MSP of the nasal cavity in an 83-year-old man with no evidence of immunodeficient state. The resected tumor consisted of spindle cells, which contained numerous acid-fast bacilli in the cytoplasm. By polymerase chain reaction and sequencing using DNA extracted from the paraffin sections, the bacilli were identified as Mycobacterium intracellulare. Immunohistochemistry revealed that the spindle cells were positive for CD68, CD11c and S100 protein, confirming the histiocytic nature of these cells. They were also positive for CD163 and CD204, suggesting that they showed a phenotype similar to alternatively activated (M2) macrophages and the phenotype might contribute to the maintenance of mycobacterial infection despite apparent immunocompetence of the host.

Histopathological findings in immunohistological staining of the granulomatous tissue reaction associated with tuberculosis

Purpose. The histological diagnosis of Mycobacterium tuberculosis (MTB) remains a diagnostic challenge despite different methods. Immunohistochemistry (IHC) not only could confirm granulomatous tissue involvement but also can demonstrate MTB antigen immunolocalization. This study tries to clarify the details of immunohistochemical staining for MTB with pAbBCG. Materials/Methods. Twenty-three confirmed TB granulomatous tissue samples were studied by Ziehl-Neelsen and immunohistochemistry (IHC) staining with pAbBCG. Samples were selected from the archive of the Department of Pathology, National Research Institute of Tuberculosis and Lung Disease, Tehran, Iran. Results. IHC staining was positive in all samples, whereas Ziehl-Neelsen was positive in 9 cases out of 23 (39.1%). Tissue types used were pleural tissue, lymph nodes, and lung tissue. IHC showed positive coarse granular cytoplasmic and round, fragmented bacillary staining. In this study, epithelioid cells clearly showed more positive staining at the periphery of the granuloma rather than the center of granuloma. There is also positive staining in endothelial cells, fibroblasts, plasma cells, lymphocytes, and macrophages outside the granuloma. Conclusion. Considering the criteria of positive immunohistochemical staining of TB granulomatous reactions, this stain not only highlights the presence of mycobacterial antigens for tissue diagnosis, but also could morphologically localize its distribution in different cells.

Positive ProbeTec tests in fresh specimens from malignant musculoskeletal tumors: a case series

OBJECTIVE

To report a case series of patients with high-grade musculoskeletal sarcomas whose biopsies of fresh specimens yielded positive Becton Dickinson ProbeTec tests, in addition to confirming diagnoses of high-grade sarcomas.

METHODS

Fresh biopsies of high-grade musculoskeletal sarcomas were subjected to ProbeTec tests.

RESULTS

The biopsies of three Chinese patients aged 65, 49 and 78 years with high-grade musculoskeletal sarcomas had positive Becton Dickinson ProbeTec tests. These patients' overall clinical pictures were not consistent with active tuberculous infections, which suggested that the ProbeTec test results were false-positives. The reason for this is not known but it is postulated that there is homology between the primers used for the ProbeTec test and the molecular properties of high-grade sarcomas.

CONCLUSION

With the increasing use of the ProbeTec test in clinical practice, fellow surgeons and pathologists are encouraged to be aware of this phenomenon.

Mycobacterial spindle cell pseudotumor of the lung

Mycobacterial spindle cell pseudotumor (MSP) is a rare benign lesion characterized by local proliferation of spindle-shaped histiocytes containing acid-fast mycobacteria. Most reported cases of MSP occur in the lymph nodes, skin, spleen, and brain in patients who are immunocompromised, particularly following solid organ transplant and in those with AIDS. This is a case report of a patient with AIDS who presented with cough, generalized weakness, and fatigue, who was found to have multilobar lung masses that were MSP, which to our knowledge has not yet been reported in the literature.

[Infectious lymphadenitis]

Infectious lymphadenitis is often biopsied in the differential diagnoses of malignant disease. Since the repertoire of lymph nodes which react to exogenous stimuli is limited, malignant lymphomas may enter the clinical and morphological differential diagnosis. In a morphological sense, infectious lymphadenitis is defined as an infection of lymph node tissue. Therefore, the effector phase of the inflammatory reaction will act against lymphatic tissue, in contrast to common physiological hyperplasia. Follicular reactions, in addition to follicular hyperplasia, are seen in HIV-associated lymphadenopathy. Other viruses, such as infectious mononucleosis, give rise to a cytotoxic T-cell reaction. Most infections, however, induce a histiocytic reaction; depending on the microorganism, this varies morphologically from a small clustered epithelioid cell reaction or histiocytic abscesses to epithelioid necrotizing granulomata.

Recognition of Dual or Multiple Pathology in Skin Biopsies from Patients with HIV/AIDS

A large percentage of patients with HIV/AIDS will develop dermatological complications. Consequently, all practising clinicians and pathologists in regions with a high prevalence of HIV/AIDS must be familiar with the diverse cutaneous manifestations of the disease. This paper highlights the fact that biopsy material in this clinical context may occasionally reveal more than one pathological process. The potential spectrum includes two or more infections in a single skin biopsy (e.g., herpes simplex and cytomegalovirus infection), neoplastic lesions containing infective organisms (Kaposi sarcoma (KS) and cryptococcosis), dermatoses in association with neoplastic lesions (e.g., KS and interface dermatitis), or more than one dermatosis in a given specimen (e.g., papulopruritic eruption and nodular prurigo). Rare biopsies may even demonstrate triple pathology. The importance of careful examination of skin biopsies in this clinical context is emphasised. Failure to recognise an undiagnosed concomitant opportunistic infective pathogen could have potentially disastrous consequences for the patient.

Review of HIV-Related Cytopathology

Exfoliative and aspiration cytologies play a major role in the management of patients with human immunodeficiency virus infection. Common cytology samples include cervicovaginal and anal Papanicolaou tests, fine needle aspirations, respiratory specimens, body fluids, Tzanck preparations, and touch preparations from brain specimens. While the cytopathologists need to be aware of specific infections and neoplasms likely to be encountered in this setting, they should be aware of the current shift in the pattern of human immunodeficiency virus-related diseases, as human immunodeficiency virus patients are living longer with highly active antiretroviral therapy and suffering fewer opportunistic infections with better antimicrobial prophylaxis. There is a rise in nonhuman immunodeficiency virus-defining cancers (e.g., anal cancer, Hodgkin's lymphoma) and entities (e.g., gynecomastia) from drug-related side effects. Given that fine needle aspiration is a valuable, noninvasive, and cost-effective tool, it is frequently employed in the evaluation and diagnosis of human immunodeficiency virus-related diseases. Anal Papanicolaou tests are also increasing as a result of enhanced screening of human immunodeficiency virus-positive patients for cancer. This paper covers the broad spectrum of disease entities likely to be encountered with human immunodeficiency virus-related cytopathology.

Cutaneous colesional acquired immunodeficiency syndrome associated Kaposi sarcoma and cryptococcosis

The clinicopathologic features of 4 AIDS patients with cutaneous colesional Kaposi sarcoma (KS) and cryptococcosis, a rare phenomenon, are described. Biopsies from 3 patients who were highly active antiretroviral therapy (HAART)-naive demonstrated predominant KS with a conspicuous spindle cell component and small aggregates of cryptococcal yeasts in 2 biopsies and predominant gelatinous cryptococcosis with attenuated KS spindle cells in 1 biopsy. One patient was HAART exposed. He had childhood pulmonary tuberculosis, was treated for disseminated cutaneous cryptococcosis 18 months earlier and presented with cutaneous lesions, odynophagia and massive cervical lymphadenopathy in the eighth week of HAART, after achieving viral suppression and a CD4 cell increase from 28 to 184 cells/μL. His skin biopsy demonstrated a dense lymphoplasmacytic infiltrate, neutrophils, and granulomas with admixed aggregates and single Cryptococcus neoformans and focal aggregation of human herpes virus 8-immunopositive spindle cells. Acid fast bacilli were not identified and mycobacterial molecular studies were negative. The features were compatible with cutaneous cryptococcal immune reconstitution inflammatory syndrome. His nodal and oropharyngeal biopsies demonstrated dense mixed, including granulomatous, inflammation with few cryptococcal yeasts and acid fast bacilli, confirmed to be Mycobacterium tuberculosis on polymerase chain reaction testing, without KS. These features were also compatible with immune reconstitution inflammatory syndrome, but the exact role of each infection in the extracutaneous sites was unconfirmed. Colesional KS and cryptococcosis served as the sentinel lesion of AIDS in 3 patients and of immune reconstitution inflammatory syndrome in 1 patient.

Clinical history of HIV infection may be misleading in cytopathology

Human immunodeficiency virus (HIV)-infected patients are at an increased risk for developing opportunistic infections, reactive conditions and neoplasms. As a result, a broad range of conditions are frequently included in the differential diagnosis of HIV-related lesions. The clinical history of HIV infection may, however, be misleading in some cases. Illustrative cases are presented in which knowledge of a patient's HIV status proved to be misleading and increased the degree of complexity of the cytologic evaluation. Case 1 involved the fine needle aspiration (FNA) of a painful 3 cm unilateral neck mass in a 38-year-old female with generalized lymphadenopathy. Her aspirate revealed a spindle cell proliferation devoid of mycobacteria that was immunoreactive for S-100 and macrophage markers (KP-1, PGM1). Multiple noncontributory repeat procedures were performed until a final excision revealed a schwannoma. Case 2 was a CT-guided FNA of a positron emission tomography positive lung mass in a 53-year-old man. The acellular aspirate in this case contained structures resembling fungal spore forms that were negative for mucicarmine and GMS stains, as well as cryptococcal antigen immunocytochemistry. A Von Kossa stain confirmed that these pseudo-fungal structures were calcified debris. Follow up revealed multiple calcified lung and hilar node based granulomata. Case 3 involved the cytologic evaluation of pleural fluid from a 47-year-old man with Kaposi sarcoma and recurrent chylous pleural effusions. Large atypical cells identified in his effusion were concerning for primary effusion lymphoma. Subsequent pleural biopsy revealed extramedullary hematopoiesis, documenting these atypical cells as megakaryocytes. These cases demonstrate that knowledge of a patient's HIV status can be misleading in the evaluation of cytology specimens, with potential for misdiagnosis and/or multiple procedures. To avoid this pitfall in the setting of HIV infection, common entities unrelated to HIV infection and artifacts should always be included in the differential diagnosis.

Dermatopathological challenges in the human immunodeficiency virus and acquired immunodeficiency syndrome era

The histopathological assessment of cutaneous lesions is critical to the definitive diagnosis of many human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome-associated dermatoses, infections and tumours. Dermatopathological challenges stem mainly from the altered histopathological profile of established cutaneous entities compared with that in the HIV-unaffected population, the emergence of new diseases and the impact of therapeutic modalities on cutaneous lesions. This review focuses on some of these diagnostic dilemmas, with emphasis on the following challenges: (i) infective diagnostic pitfalls; (ii) itchy papular skin lesions; (iii) co-lesional comorbid diseases; (iv) drug-induced disease alterations; and (v) neoplastic and pseudoneoplastic proliferations. The drug-induced alterations include highly active antiretroviral therapy-associated disease modifications.

Granulomas in acquired immunodeficiency syndrome-associated cutaneous Kaposi sarcoma: evidence for a role for Mycobacterium tuberculosis

BACKGROUND

Co-lesional acquired immunodeficiency syndrome-associated cutaneous Kaposi sarcoma (AIDS-KS) and Mycobacterium tuberculosis-associated granulomatous inflammation are undocumented.

METHOD

Retrospective appraisal of skin biopsies with co-lesional AIDS-KS and microscopic tuberculosis (TB).

RESULTS

Sixteen biopsies from nine males and seven females form the study cohort. Histological assessment confirmed nodular and plaque KS in 12 and 4 cases each, respectively. Necrotizing, non-necrotizing and a combination of necrotizing and non-necrotizing granulomatous inflammation were present in nine, two and five biopsies each, respectively. The identification of acid fast bacilli on Ziehl-Neelsen staining and M. tuberculosis on polymerase chain reaction confirmed co-lesional TB in 15/16 biopsies. Co-lesional AIDS-KS and lichen scrofulosorum, hitherto undocumented, were confirmed in one biopsy. The histopathological findings served as a marker of human immunodeficiency virus (HIV) infection, visceral TB, therapeutic noncompliance and multidrug resistant pulmonary TB in nine, eight, five and one patient, respectively. M. tuberculosis was cultured from sputum or nodal tissue of all patients.

CONCLUSION

Granulomatous inflammation in KS requires optimal histopathological and molecular investigation to confirm an M. tuberculosis origin. The cutaneous co-lesional occurrence of AIDS-KS and microscopic TB may serve as the sentinel clue to HIV infection, systemic TB, therapeutic noncompliance or multidrug resistant TB.

Inflammatory myofibroblastic tumor of the liver due to Mycobacterium tuberculosis in an immunocompetent girl

The case of a 9-year-old girl with a Mycobacterium tuberculosis inflammatory myofibroblastic tumor (IMT) of the left lobe of the liver is reported. The tumor was surgically excised and had histological features diagnostic of IMT, a positive Ziehl-Nielsen staining for acid-fast bacilli and a positive polymerase chain reaction for Mycobacterium tuberculosis. Surgical excision of the tumor followed by anti-tuberculosis treatment for 9 months resulted in full recovery. The patient had no apparent immune disorder, and there was no evidence of extrahepatic tuberculosis. These findings make this case exceptional because IMTs, due mostly to atypical mycobacteria, have been described only in immunocompromised patients.

Nodal inflammatory pseudotumor caused by luetic infection

Inflammatory pseudotumor of lymph nodes (IPT-LN) represents an unusual cause of lymphadenitis of unknown etiology. Upon the observation of a case of IPT-LN associated with Treponema pallidum (Tp) infection, we analyzed a series of 9 IPT-LN and 9 extranodal IPT (spleen, 4 cases; lung, orbit, gut, skin, and liver) for the presence of Tp, using a polyclonal antibody anti-Tp. At the time of biopsy, none of the patients was suspected for luetic infection, nor specific serologic tests were available. IPT-LN areas extensively involved the nodal parenchyma in 4 cases, whereas they were focal in the remaining 5 cases. Capsular thickening and inflammation (6/9), venulitis (3/9), small granulomas (3/9), and follicular hyperplasia (7/9) were observed in the associated lymphoid parenchyma. Tp were detected in 4/9 cases of LN-IPT and in none of the extranodal IPT. Tp were extremely abundant within the IPT areas and in the perivascular tissues in the surrounding parenchyma, whereas they were scattered within the capsule. In Tp+ cases, marked follicular hyperplasia was the single distinctively associated feature. Double immunostains revealed that Tp were predominantly contained in the cytoplasm of CD11c+ CD163+ macrophages, some of which co-expressed HLA-DR. In addition, scattered S100+ interdigitating dendritic cells also showed intracytoplasmic Tp. This study shows that a significant number of IPT-LN is associated with Tp infection. A spirochetal etiology can be suspected in cases of IPT-LN, independently from the extension of the lesions, especially when pronounced follicular hyperplasia is found. Infection by Tp of macrophages and dendritic cells are in keeping with in vitro data and indicate that immune mediated mechanisms may be involved in the pathogenesis of the lesions.

Nontuberculous mycobacterial infections

CONTEXT

Nontuberculous mycobacteria include numerous acid-fast bacilli species, many of which have only recently been recognized as pathogenic. The diagnosis of mycobacterial disease is based on a combination of clinical features, microbiologic data, radiographic findings, and histopathologic studies.

OBJECTIVE

To provide an overview of the clinical and pathologic aspects of nontuberculous mycobacteria infection, including diagnostic laboratory methods, classification, epidemiology, clinical presentation, and treatment.

DATA SOURCES

Review of the pertinent literature and published methodologies.

CONCLUSIONS

Nontuberculous mycobacteria include numerous acid-fast bacilli species, many of which are potentially pathogenic, and are classified according to the Runyon system based on growth rates and pigment production. Their slow growth hinders cultures, which require special medium and prolonged incubation. Although such methods are still used, newer nucleic acid-based technologies (polymerase chain reaction and hybridization assays) can rapidly detect and speciate some mycobacteria--most notably, distinguishing Mycobacterium tuberculosis from other species. Infections caused by these organisms can present as a variety of clinical syndromes, not only in immunocompromised patients but also in immunocompetent hosts. Most common among these are chronic pulmonary infections, superficial lymphadenitis, soft tissue and osteoarticular infections, and disseminated disease. Treatment of nontuberculous mycobacterial infections is difficult, requiring extended courses of multidrug therapy with or without adjunctive surgical intervention.

Gastrointestinal malignancies in HIV-infected or immunosuppressed patients: pathologic features and review of the literature

The gastrointestinal (GI) tract is a common internal organ to be involved by human immunodeficiency virus (HIV)-related malignancies. It is the second most common site for Kaposi sarcoma after skin, and the commonest visceral site, for Kaposi sarcoma in AIDS patients. GI lymphomas have been documented in approximately 25% of AIDS patients with systemic lymphomas. Moreover, GI involvement of AIDS-lymphoma has been associated with poor prognosis and short survival. Several other malignancies that occur in the GI tract are also closely related to HIV-infected or immunosuppressed individuals; these include posttransplant lymphoproliferative disorder, Epstein-Barr virus-associated smooth muscle tumors, anal precancerous lesions, and squamous cell carcinoma. As a result of active antiretroviral therapy, patients infected with HIV are living longer and are consequently at increased risk for development of cancer. Therefore, it is possible that the number of AIDS-associated malignancies will rise and the pattern of tumors may change in the future. In this paper, the clinicopathologic features of GI malignancies associated with AIDS patients are reviewed and the differential diagnosis with other mimic lesions is discussed.

Cryptococcal Inflammatory Pseudotumors

"Inflammatory pseudotumors" (IPTs) embrace a heterogeneous spectrum of reactive, infective, and neoplastic entities, that are characterized by a clinical mass composed of a histologic proliferation of spindle cells in a background of inflammatory cells and collagen fibers. Although a spectrum of microorganisms have been identified in infective IPTs, mycobacterial infective IPTs are reported most commonly. We document 5 solitary cryptococcal IPTs, in 2 males and 3 females, aged 19 to 43 years, in the soft tissues of the anterior chest wall, thigh, and arm. All were HIV-positive and had been treated for disseminated cutaneous and/or meningeal cryptococcosis with antifungal therapy, 6 to 12 months earlier. The specimens demonstrated a storiform arrangement of plump spindle cells, in addition to spindle and polygonal cells that were arranged in a haphazard manner. Background lymphocytes, plasma cells, and fibrosis were noted, in addition to scattered giant cells and focal necrosis. On high-power examination, Cryptococcus neoformans yeasts were identified within and between vacuolated spindle and polygonal cells on routine and special stains, confirming cryptococcal IPTs. Immunophenotyping of the spindle cells confirmed a mixed histiocytic and myofibroblastic lineage, with a predominance of the former. In documenting 5, hitherto unreported, pseudotumoral spindle cell reactions to C. neoformans, we not only highlight the need for intense appraisal of all IPTs for infective agents on routine and special stains and investigations, but also postulate that a complex host-fungus interaction, coupled with an exuberant, myofibroblastic response to incomplete therapy, are the pathogenetic drive for the pseudotumoral presentation.

Mycobacterial spindle cell pseudotumor of the skin

BACKGROUND

Mycobacterial spindle cell pseudotumor is a rare tumor-like lesion characterized by the proliferation of spindle cells engorged with mycobacterial microorganisms. To our knowledge, only a few cases of cutaneous lesions have been described in the literature.

CASE REPORT

A 58-year-old Japanese woman presented with a nodule in her left forearm. She had systemic lupus erythematosus and interstitial pneumonia for 17 years, treated with prednisolone and azathioprine. She was also receiving insulin treatment for diabetes mellitus.

RESULTS

Histologically, the lesion was located in the deep dermis with extension into the subcutaneous fat tissue and was composed mainly of spindle cells focally showing a vaguely storiform pattern. In limited focal areas, foam cells, epithelioid histiocytes, and multinucleated giant cells were seen sparsely. Ziehl-Neelsen staining showed numerous acid-fast bacilli within the spindle cells and epithelioid histiocytes. The acid-fast bacilli were determined by culture and polymerase chain reaction to be Mycobacterium intracellulare.

CONCLUSIONS

We emphasize that mycobacterial spindle cell pseudotumor should be included in the differential diagnoses of a spindle cell lesion in the skin, especially in immunosuppressed patients.

Inflammatory pseudotumor of the liver in a patient with congenital granulocytopenia and HCV infection

Inflammatory pseudotumor (IPT) of the liver is a rare pathologic lesion. Although IPTs within the liver shows spontaneous regression, these lesions are frequently misdiagnosed as malignant on the basis of the clinical manifestation and the results of diagnostic imaging. With special regard to magnetic resonance imaging (MRI), differential diagnosis such as hepatocellular or cholangiocellular carcinoma (HCC/CCC) as well as regenerative liver lesions are discussed in a case of IPT with concomitant hepatitis C virus (HCV) infection and congenital granulocytopenia.

Fine-needle aspiration diagnosis of Kaposi's sarcoma in a developing country

Fine-needle aspiration (FNA) cytology was performed on 15 patients with peripheral lymphadenopathy and/or skin lesions referred to the Department of Pathology of the Hospital Central of Maputo, Maputo, Mozambique. Epitrochlear lymph nodes were the most frequently aspirated site. All aspirates allowed diagnoses of Kaposi's sarcoma (KS). Smears contained loosely cohesive clusters of bland spindle cells, with a radial arrangement and nuclear crush artifacts. These diagnostic clues have not been described in other spindle-cell intranodal lesions that should be considered in differential diagnoses. Taking into consideration the high prevalence of AIDS and limited resources for diagnosis in Africa, FNA cytology appears to be a useful method for the diagnosis of KS in developing countries, reducing the necessity for surgical lymph node excision.

The enigmatic inflammatory pseudotumours: the current state of our understanding, or misunderstanding

The inflammatory pseudotumour is a bona fide tumour in the sense of a mass lesion, which is known to present in virtually every anatomic region and organ from the central nervous system to the gastrointestinal tract. A fundamental question about pathogenesis is whether the inflammatory pseudotumour is a pseudo-or true neoplasm. There is evidence to support the argument that some of these fibroinflammatory masses are infection-associated and are often characterized by a proliferation of spindled histiocytes and/or dendritic cells, in contrast to a myofibroblastic proliferation in the other inflammatory pseudotumour, also known as the inflammatory myofibroblastic tumour.

Adjuvant therapy with hyaluronidase prior to excision of dermatofibrosarcoma protuberans

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) are uncommon, low grade cutaneous malignancies, which rarely metastasize. Although surgery is the main therapy for these tumors, they commonly recur in spite of wide excisions. Hyaluronidase (HD) has been used both intralesionally as well as intravenously as an adjuvant in therapy of both epithelial and mesenchymal malignancies to decrease local spread, to potentiate differentiation induced apoptosis, and to potentiate the tissue penetration of chemotherapeutic agents. In addition, there is a long history of intralesional HD use without significant complications. The biologic characteristics of DFSP including the observation that hyaluronic acid is commonly present and sometimes is increased in these tumors and the known effects of HD therapy in other malignancies suggested to us that HD pretreatment may be a helpful adjuvant in the surgical management of DFSPs. Following diagnostic biopsy of a recurrent DFSP, the patient was treated for 4 weeks with intralesional HD injections.

RESULTS

Based on margins necessary for complete excision from past studies, this patient had decreased margin width and thus had a postoperative wound size less than was expected. The patient has had no evidence of recurrence at 24 months follow-up.