Endobronchial leiomyoma: an unusual non-defining neoplasm in a patient with AIDS

Leiomioma endobronquial: rara neoplasia não definida em paciente com AIDS

CASE REPORT

Endobronchial leiomyoma: an unusual non-defining neoplasm in a patient with AIDS

Leiomioma endobronquial: rara neoplasia não definida em paciente com AIDS

Humberto Metta^I; Marcelo Corti^I; Liliana Redini^I; Roberto Dure^I; Ana M. Campitelli^I; Marina Narbaitz^II

^IInfectious Diseases F.J. Muñiz Hospital, Buenos Aires, Argentina

^IINational Academy of Medicine, Buenos Aires, Argentina

^{Correspondence to}

SUMMARY

Smooth muscle neoplasms are more frequent in human immunodeficiency infected children than in HIV seropositive adults. Endobronchial leiomyoma is a rare benign tumor in HIV infected adult patients. Epstein-Barr virus (EBV) has been implicated in the pathogenesis of these tumors. Here we describe an adult patient with HIV infection with atelectasis of the left upper pulmonary lobe as the first clinical expression of an intrabronchial leiomyoma. In this case, we can not show the association with EBV. Our report suggests that smooth muscle tumors as leiomyoma should be included in the differential diagnosis of endobronchial masses in AIDS patients.

Keywords: Endobronchial leiomyoma; Atelectasis; AIDS; HIV.

RESUMO

Neoplasmas da musculatura lisa são mais freqüentes em crianças infectadas pelo vírus da imunodeficiência humana do que em adultos HIV-soropositivos. Leiomioma endobronquial é um tumor benigno em pacientes adultos infectados por HIV. Vírus Epstein-Barr (EBV) tem sido implicado na patogenia destes tumores. Descrevemos paciente adulto infectado pelo HIV com atelectasia do lobo pulmonar superior esquerdo como primeira manifestação clínica de leiomioma intrabronquial. Neste caso não pudemos demonstrar a associação com EBV. Nosso relato sugere que tumores de musculatura lisa como leiomioma deveriam ser incluídos no diagnóstico diferencial de massas endobronquiais em pacientes com AIDS.

INTRODUCTION

Epstein-Barr virus-associated smooth muscle tumors (EBV-SMT) include leiomyomas and leiomyosarcomas which are the second most prevalent malignancy in children with AIDS⁷. These tumors are not very common in adults and can be located in the soft tissue³ and in the gastrointestinal tract¹⁰ and less frequently in the liver¹⁴, the spleen¹, the adrenal gland, the urinary tract including the kidneys and the gallbladder¹⁶ and the central nervous system (meninges and spinal neural canal)¹². EBV-SMT in adults with AIDS are extremely rare, with only few cases involving the respiratory tract reported in the literature⁶.

We present a case of an adult HIV/AIDS patient who developed an endobronchial leiomyoma without evidence of an association with EBV.

CASE REPORT

A 36 year-old HIV seropositive man with diagnosis of AIDS on account of history of cryptococcal meningitis and Pneumocystis jiroveci pneumonia, presented with fever (39 °C), progressive dyspnea, productive cough and weigh loss (approximately 5 k weight during the last month). The chest radiograph revealed atelectasis of the left upper lobe plus a left pleural effusion. A computed tomography showed the same findings (Fig. 1). The CD4 T cell count was 9 cells/µL (3%). Flexible fiberoptic bronchoscopic examination disclosed a left endobronchial lobulated tumor that obstructed the ostium of the left upper lobe, as the cause of the atelectasis (Fig. 2). It was completely removed and atelectasis was resolved. Histopathologic examination revealed the smooth muscle origin of this tumor by the routine microscopy. The diagnosis was confirmed by means of a positive immunostaining for smooth muscle actin. Histologic features were mesenchymal tumor characterized by the fusocellular proliferation of spindle cells with cigar-shaped nuclei, eosinophilic fibrillar cytoplasms and hialinosis areas, compatible with smooth muscle tumor (Fig. 3). No mitosis was found in the biopsy specimen. There was relation between the tumor and the smooth muscle with the bronquial wall. The tumor cells showed immunoreactive for specific antismooth muscle actin and HHF35 actin expression (Fig. 4), with no expression of CD117, S-100, CD34 and HMB45, consistent with the histopathological diagnosis of leiomyoma. The detection of EBV by in situ hibridization (ISH) for EBV-encoded RNA-1 (EBER-1) and for EBV associated latent membrane protein-1 (LMP-1) by immunohistochemical (IHQ) in formalin fixed, parafin embebed tissue, were negative. During a twelve-month follow-up period, the patient upholds normal respiratory function with no evidence of tumor recurrence (Fig. 5).

DISCUSSION

Tumors of smooth muscle origin rarely involve the lung. Among all tumors surgically excised from the lung, only 4% are benign and, of these, only 2% are leiomyomas, a benign form of smooth muscle tumor^3,15.

Human immunodeficiency virus (HIV)-infected adults have an increased risk to develop some non-AIDS defining neoplasms, as Hodgkin lymphoma and lung carcinoma, but leiomyoma remains rare and generally involves extrapulmonary sites^{1,3,6,10,11,12,14,16}. In adults, these tumors should be described in immunocompromised patients with renal transplantation, steroid therapy and AIDS⁵.The first case of an endobronchial leiomyoma in an adult with AIDS was described by BLUHM et al.³ in 1997. In the lung, leiomyoma usually involves the bronchi or alveolar wall and it is presented as a solitary lesion, as in the patient we are describing. However, in the case which was presented by BLUHM the neoplasm was multifocal³.

Endobronchial lesions in adults with HIV include malignancies as Kaposi´s sarcoma and non-Hodgkins lymphoma and several infectious diseases as tuberculosis and other mycobacteriosis⁴. Due to the similar aspects of bronchoscopic appearance of these different complications of advanced HIV/AIDS disease, the endobronchial or bronchoscopic lung biopsies with special stains (Ziehl-Neelsen, Grocott, Giemsa), should be performed to guarantee the final diagnosis.

Definitive criteria for determining malignancy of SMT, specifically leiomyosarcoma located outside the digestive and genitourinary tracts, includes the size, cellularity, cytologic atypia, necrosis grade and the presence of hemorraghic areas. The most important predictor of malignancy is the level of mitotic activity in the atypical cells that varies by the organ involved⁶.

The relationship between EBV infection and the risk of the development of smooth muscle tumors have been well described in the medical literature, especially in tumors affecting children with AIDS and immunosuppressed individuals after liver or renal transplantation⁹. These reports suggest that EBV infection may play a role in the pathogenesis of these tumors in immunocompromised children. Also, the presence of EBV genome in the tumor tissue from HIV-infected adults should be shown and suggests that EBV is implicated in the development of tumors of the smooth muscle in immunocompromised adults³.

However, there were several reports in which leiomyomas were not related with EBV and ISH was negative, as in our patient¹⁶. Such features were reported in non-AIDS and immunocompetent hosts^2,8. These cases marked that other mechanisms also may contribute to develop this kind of tumors, including the retrovirus HIV, in a direct or indirect way⁹. The tumor present in the case we are describing is not identical, in strict sense, to those with EBV associations that are common to AIDS.

In conclusion, endobronchial leiomyoma is still a rare benign tumor in HIV-infected adult patients. Histopathological features are the source to certify the final diagnosis, which is difficult to be suspected only of clinical expression.

Our report suggests that, if the diagnosis of leiomyoma is more an exception than a rule, SMT should be included in the differential diagnosis of endobronchial masses associated with atelectasis in HIV/AIDS patients.

Received: 23 January 2008

Accepted: 30 October 2008

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Publication Dates

• Publication in this collection
  12 Feb 2009
• Date of issue
  Feb 2009

History

• Received
  23 Jan 2008
• Accepted
  30 Oct 2008