Significance of Charcot Leyden crystals in hepatic aspirates.

Charcot Leyden crystals are hexagonal bipyramidal structures localised in the primary granules of the cytoplasm of eosinophils and basophils. Their presence, along with eosinophilic infiltrate, is an indirect evidence of parasitic infestation particularly with Toxocara, Capilliriasis, Ascariasis, or Fasciola. We report here two cases where Charcot Leyden crystals with eosinophilic infiltrate were found in the smears prepared from hepatic abscess.

Introduction

Charcot Leyden crystals are hexagonal bipyramidal structures named after J. M. Charcot who first described it in 1853. They are also known as Arthus crystals and Charcot Robins crystals. These crystals are about 50 microns in length and are composed of lysophospholipase enzyme that inactivates cell-damaging lysophosphatides produced during membrane metabolism during degranulation.[1] These are localised in the primary granules of the cytoplasm of eosinophils and basophils,[2] and there is often formation of Charcot Leyden crystals during intense or prolonged eosinophilic inflammatory reaction.[1] As reported in the literature, their presence may indicate infestation with parasites like Toxocara, Capilliriasis, Ascariasis, or Fasciola.[37-11] Sometimes, they may be found within macrophages in the vicinity of conglomerates of eosinophils, representing a disposal system by macrophages. These crystals were first observed in a patient with leukemia and later in the mucous plugs in asthma patients.[4] However, they are not usually seen on direct microscopic examination of the aspirate or in the histopathology section in liver abscesses. Here, we report two cases where abundant Charcot Leyden crystals were found in the smears prepared from hepatic abscess.

Case Reports

Case 1

A seven year-old male child from a rural area presented with mild pain over his right upper abdomen and sporadic fever of six months’ duration. Examination revealed that the liver was palpable five cm below the right subcostal margin and was tender; there was no other organomegaly. Routine hematological investigations and liver function test results were within normal limits. On clinical suspicion of liver abscess, a computed tomography (CT) scan was done which showed multiple, small (one cm), hypodense shadows, some with central hypoechoic zones. A provisional diagnosis of liver abscess was made. Fine needle aspiration from the mass was done and pus was aspirated. Smears prepared from the aspirate showed an abundance of hexagonal, needle-shaped Charcot Leyden crystals in a background of degenerated hepatocytes, necrotic material, and mixed inflammatory infiltrate predominantly consisting of eosinophils [Figure 1]. No trophozoites or parasites could be demonstrated and culture of the aspirated pus was sterile. A thorough stool examination of the child showed no ova or cysts. Parasitic infestation was suspected and the patient was treated with anthelminthics to which he responded well.

Figure 1

Smear showing hexagonal Charcot Leyden crystals in a background of inflammatory cells and necrotic material (MGG, ×400)

Case 2

A 50 year-old female patient presented with fever and right upper abdominal pain of fifteen days's duration. She had lost appetite and weight over the last two months. Examination revealed that her liver was enlarged three cm below the right subcostal margin. Her routine hematological analysis was as follows: hemoglobin - 10.6 g/dL, hematocrit - 32.5%, total leucocyte count - 15,300/mm3, differential leukocyte count - polymorphs: 60%, lymphocyte: 15%, eosinophil: 23%, monocyte: 2%. Ultrasonography of the upper abdomen showed a solitary hypoechoic lesion with irregular borders, 3.5 cm in diameter, suggestive of a hepatic abscess or neoplastic lesion. Fine needle aspiration was done from the lesion and the smears showed abundant, hexagonal, needle-shaped Charcot Leyden crystals in a background of degenerated hepatocytes, necrotic material, and mixed inflammatory infiltrate predominantly consisting of eosinophils. At places, poorly formed epithelioid cell granulomas were also seen [Figure 2a and b] but Ziehl Neelsen staining for acid-fast bacilli was negative. A possibility of helminthic infestation was considered and the patient was treated with anthelminthics. After a full course of antihelminthics, her routine hemogram was repeated and an excellent improvement was seen: total leucocyte count - 9,000/mm3, differential leucocyte count - polymorphs - 70%, lymphocyte - 20%, eosinophil - 8%, monocyte - 2%.

Figure 2a

Spindle-shaped Charcot Leyden crystals in a necrotic background (MGG, ×400)

Figure 2b

A poorly formed epithelioid cell granuloma with inflammatory cells and necrotic debries (MGG, ×400)

Discussion

The common cause of pyogenic liver abscess in children is reported to be visceral larva migrans by Toxocara species.[5] Most of the cases remain subclinical but symptomatic patients may present with fever, malaise, weakness, pruritus, rash or urticaria, abdominal pain, anorexia, cough, dizziness, and weight loss.[6] Hepatosplenomegaly is common;[6] a long-standing, high eosinophil count is a characteristic diagnostic feature (may be up to 90%).[6] CT images show small, scattered, hypodense, nodular lesions of varying sizes (usually < 1 cm); rarely a large, abscess-like lesion up to 7–10 cm can be found.[6] Histologically, the lesion shows granulomas consisting of aggregates of eosinophils and other inflammatory cells and tissue necrosis.[6] Less frequently, Charcot Leyden crystals with eosinophilic infiltrate and, rarely, parasitic remnants are seen in the biopsy tissue.[3] The illness may persist from several months to years.[6] In the first case, the only point against the diagnosis was the absence of peripheral eosinophilia. However, there are reports that highlight that visceral larva migrans should be suspected as the cause of a chronic liver disease in patients without fever and hypereosinophilia with cryptogenic cholestatic and focal liver lesions.[78] The age of presentation, poor socioeconomic status, and the characteristic CT scan findings of hepatic lesions along with the fine needle aspiration smear findings (plenty of Charcot Leyden crystals in a background of degenerated hepatocytes, necrotic material, and mixed inflammatory infiltrate, predominantly consisting of eosinophils) favoured a diagnosis of parasitic nature. Although no parasite could be demonstrated in the fine needle aspiration smears as well as by stool examination, a probable diagnosis of parasitic infestation, particularly with Toxocara species, was considered. The patient was treated accordingly and he responded well. Another possibility of such a presentation may be infestation with Capillaria hepatica, but it usually affects small children living in unsanitary environments infested with rats; no such history was present here.

In adults presenting with similar clinical features of liver disease, a radiologically evident solitary hepatic lesion along with peripheral eosinophilia can pose as a diagnostic problem. Differential diagnosis in these cases may include Fasciola infestation, inflammatory pseudotumor, and neoplastic lesion. In Asian countries, Fasciola gigantic is more common than Fasciola hepatica.[4] Whatever the cause, Fasciola infestation presents with acute illness with symptoms of fever, abdominal pain, headache, rash, or urticaria.[6] A biphasic pattern of peripheral eosinophilia is very common[6] and liver function test results are either normal or slightly raised.[6] Solitary or multiple migratory abscesses that change in shape, size, and position over time and are evident radiologically particularly in CT scans are a very characteristic feature of Fasciola infestation.[6] In the chronic stage, the patient may become asymptomatic or may have episodes of some nonspecific symptoms.[6] In the present case, although the features were quite suggestive of Fasciola infestation, it was not considered as diagnosis due to its rare occurrence in India and inability to detect any parasite.

Hepatic inflammatory pseudotumor is a rare benign lesion that has the features of fever, pain, and the hepatic mass. The etiology and pathogenesis are uncertain but infection or parasitic infestation may be possible causes. Three cases reported in the literature include one case caused by E. coli, another by Gram-positive cocci, and in the third one, ascaris larvae were demonstrated in the hepatic lesion.[9] Fine needle aspiration smears, as well as biopsy, mainly show intense inflammatory reaction (neutrophils, eosinophils, histiocytes, and lymphocytes) along with Charcot Leyden crystals.[9] In the present series in case 2, inflammatory reaction was not severe enough to consider the case to be an inflammatory pseudotumor.

In adults, a possibility of neoplastic and metastatic lesions should also be ruled out based on the presence of eosinophil-predominant, inflammatory infiltrate and the absence of hyperchromatic, pleomorphic cells.[612] Finally, considering the fine needle aspiration findings from the hepatic lesion of the lady (abundant, hexagonal, needle-shaped Charcot Leyden crystals in a background of degenerated hepatocytes, necrotic material, and mixed inflammatory infiltrate predominantly consisting of eosinophils with poorly formed epithelioid granulomas at places) along with peripheral eosinophilia as an indirect evidence of parasitic infestation, the patient was treated with anthelminthics and showed marked improvement.

A possibility of ‘eosinophilic granuloma’ (Langerhans cell histiocytosis) which may also show numerous Charcot Leyden crystals in a background of eosinophils,[11] was ruled out due to the absence of characterstic histiocytes with folded or grooved nuclei (Langerhans cells).

Charcot Leyden crystals with eosinophils are a common finding in the stool samples of patients with amoebic enteritis. However, they are rare in the pus from an amoebic liver abscess which mainly consists of necrosed inflammatory and parenchymal cells, red blood cells, and trophozoites of E. histolytica.[11]

Both the cases emphasise that the presence of an abundance of Charcot Leyden crystals in a background of eosinophils or eosinophilic granuloma in fine needle aspiration smears from hepatic lesions can be an indirect evidence of parasitic infestation in the absence of demonstrable parasite. These patients should be given anthelminthic treatment before considering other diagnoses even in adults, especially in a developing country like India where the incidence of parasitic infestation is high.