RAMB - Agosto 2016

ulmonary

aposi

’

sarcoma

female

patient

: C

ase

report

ssoc

ras

2016; 62(5):395-398

397

iscussion

KS associated with infection by the human immunode-

ficiency virus (HIV) is common in adult homosexual and

bisexual young men.

4-6

Men are more affected than women in a ratio of 15:1.

The annual incidence is between 0.02 and 0.06% of all ma-

lignant tumors.

KS rarely affects American or European

heterosexuals, but it often occurs in African or Caribbe-

an heterosexuals.

Most patients with pulmonary KS already present

with cutaneous lesions at the time of diagnosis; however,

visceral disease may occasionally precede the skin. The

most affected skin sites are the lower limbs, head and neck,

and the lesions may have a varied appearance (spots, pap-

ules, nodules or plaques), all palpable and non-pruritic,

with sizes ranging from millimeters to centimeters, and

brownish, pink or violet color. These lesions may also be

confluent and are generally symmetrical in distribution.

The precise incidence of pulmonary KS is still not

well known. Some clinical studies have shown a higher

prevalence in individuals with AIDS who already had the

cutaneous form of the disease (over 32%) compared to

those without it (3-13%).

3,9-11

In autopsies, however, bron-

chopulmonary KS was found in 47% of patients with

AIDS who had the cutaneous form, which reveals a pos-

sible underdiagnosis of pulmonary involvement.

Since the variety of opportunistic diseases is great,

pulmonary involvement in SK can be difficult to diag-

nose. Symptoms are unspecific (cough, dyspnea, hemop-

tysis, chest pain) and may represent several other diseas-

es, including tuberculosis. Pleural effusion, hypoxemia

and acute respiratory failure requiring mechanical venti-

lation have also been reported in some cases.

13-15

Kaposi’s sarcoma may involve the tracheobronchial

tree, the lung parenchyma and pleura. Pleural involvement

occurs only in the presence of parenchymal abnormalities,

just as the presence of lesions in the bronchial tree below

the tracheal carina is, as a rule, accompanied by parenchy-

mal lesions. In the lung, Kaposi’s sarcoma grows along

the lymph node routes, i.e. around bronchovascular sheaths,

especially in the axial interstitium, interlobular septa, and

pleura. The cellular infiltrate advances in the interstitium

along the peribronchovascular sheaths, the pulmonary

veins, and the pleural surface. From these regions, the cells

proliferate as “tentacles” to the adjacent alveolar septa and

fill the alveoli, forming solid nodules.

17,18

The diagnosis of pulmonary KS (PKS) is still a chal-

lenge, mainly because the clinical, laboratory and radio-

graphic findings are non-specific and cannot differenti-

ate PKS from other lung diseases that may occur in AIDS.

Therefore, these findings should be combined with those

obtained by CT scan, bronchoscopy and transbronchial

biopsy.

Differential diagnoses include: lymphoma, lung tu-

mors, infections (such as tuberculosis, viruses and fun-

gi), infection with

Pneumocystis jirovecii

and bacillary

angiomatosis.

18,20,21

Histologically, the tumor consists of vascular spac-

es interspersed with spindle-shaped reticuloendothelial

cell, containing atypical nuclei and occasional mitoses.

The vascular gaps contain erythrocytes and hemosider-

in deposits.

The findings on chest radiography are many, usual-

ly bilateral and diffuse. Reticulonodular infiltrates with

predilection for hilar areas and the base of the lungs, con-

solidations, multiple ill-defined nodules, bilateral pleu-

ral effusion in 30% of cases, hilar and mediastinal lymph

node enlargement in 10% of cases, and even normal x-rays

have also been described.

2,19-25

The presence of other as-

sociated lung infections may complicate the interpreta-

tion of the findings. Due to the above and the fact that

the findings are not specific of PKS, radiography has the

main role to dismiss lung involvement and/or monitor

disease progression.

High-resolution CT (HRCT) has higher sensitivity and

specificity compared to radiography in the event of sus-

pected diagnosis of PKS. Early findings include thicken-

ing of peribronchovascular interstitium, especially in the

base of the lungs, which can even simulate other oppor-

tunistic infections of the airways. Late changes include

ill-defined nodules/consolidations (“candle flame” appear-

ance) with peribronchovascular distribution, symmetri-

cal and bilateral, which may be surrounded by ground

glass opacity (halo sign), thickening of peribronchovas-

cular axial interstitium, interlobular septal thickening and

pleural effusion. These changes were observed in our pa-

tient (Figure 3). In addition to these findings, there is also

nodular thickening of fissures, subpleural nodules, hilar

and mediastinal lymph node enlargement, absent in this

case, which presented some mediastinal lymph nodes with

preserved size. In most patients, the presence of typical

nodules in CT and perihilar distribution of the aforemen-

tioned abnormalities justify KS being considered togeth-

er with other thoracic affections in AIDS.

2,15,18-20,25,27-32

onclusion

The diagnosis of pulmonary KS is still a challenge, espe-

cially due to the occurrence of other opportunistic dis-

eases that may also occur concurrently. Therefore, sus-

pecting this diagnosis based on clinical and laboratory