Hepatocellular carcinoma presenting with multiple bone and soft tissue metastases and atypical cytomorphological features--a rare case report

A case of bone metastasis of hepatocellular carcinoma: Mallory hyaline bodies can lead to the correct cytological diagnosis

Hepatocellular carcinoma (HCC) accounts for most primary tumors of the liver. Although bone metastasis does not occur in a high percentage of patients, bone metastasis is often found first, which leads to the diagnosis of HCC. In this report, we describe a case of bone metastasis from HCC in which bone lesions were detected incidentally, and in which a cytological diagnosis was difficult to make. The patient was a 78-year-old man with a history of renal dysfunction after orthopedic surgery. He underwent a thorough examination after a bone tumor was incidentally found on abdominal CT. Plasmacytoma was suspected. Fine needle aspiration cytology revealed irregular clusters of medium-to-large atypical epithelioid polygonal cells with relatively abundant eosinophilic, somewhat granular cytoplasm, and indistinct cell borders, which led to a diagnosis of malignancy. Histologically and immunohistochemically, the tumor was diagnosed as bone metastasis of HCC. Re-examination of the cytological specimen revealed characteristic Mallory hyaline bodies (MHBs). Immunohistochemistry using a cell transfer method revealed that they were positive for low molecular weight cytokeratin, Cam5.2, in a densely granular fashion. In this case, the cytological diagnosis of HCC was difficult to make due to the unclear cytoplasmic borders and absence of bile pigment. However, the identification of MHBs can potentially guide me to the correct cytological diagnosis.

Metastatic hepatocellular carcinoma to the bone diagnosed by fine needle aspiration in a veteran population

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and it may present initially with extrahepatic spread in 5%-15% cases. It most commonly metastasizes to lungs, lymph nodes and adrenal glands. Skeletal metastases from HCC are uncommon and carry a very poor prognosis.

METHODS

We retrospectively reviewed all fine needle aspiration (FNA) specimens of metastatic HCC at our institution from January 1994 to March 2021 using the SNOMED search computer option. Relevant clinical information was obtained from the review of patient's electronic medical records.

RESULTS

There were 36 FNAs of metastatic HCC over a period of 27 years. Six patients (16.7%) were found to have skeletal metastases. All six patients were males with a median age of 59 years (54-71 years) and their lesions were osteolytic. The most common site of metastases was vertebra (3/50%). Most patients (67%) had bone metastases as an initial presentation, without prior history of HCC. The mean survival after the diagnosis of skeletal metastases was only 8 months.

CONCLUSION

Detection of extrahepatic HCC to bone is important to avoid any unwanted surgical intervention. In our patient population, the most common site of skeletal metastases from HCC was vertebra, therefore in FNAs of vertebral lytic masses, metastatic HCC should be considered. On FNA, extrahepatic metastases of HCC can mimic other poorly differentiated tumors. They behave in an aggressive fashion, resulting in a grim prognosis. Cytological substrates can be used for future molecular testing, if needed.

Bone metastases as initial presentation of hepatocellular carcinoma

Extra-hepatic spread is present in 5% to 15% of patients with hepatocellular carcinoma (HCC) at the time of diagnosis. The most frequent sites are lung and regional lymph nodes. Here, we report 3 cases of unsuspected HCC with symptoms due to bone lesions as initial presentation. Morphological characteristics and immunohistochemistry from the examined bone were the key data for diagnosis. None of the patients had an already known chronic liver disease. Differential diagnoses with HCC upon ectopic liver disease or hepatoid adenocarcinoma were shown. Therapy with the orally active multikinase inhibitor sorafenib plus symptomatic treatment was indicated.