A 46-year-old Chinese woman with no significant medical history (specifically no smoking, alcohol consumption, or hepatitis) presented to our hospital with a one-year history of progressive abdominal distension and pain, particularly exacerbated after meals. One year prior, abdominal computed tomography (CT) at a local hospital had revealed a hepatic mass considered benign, for which no specific intervention was recommended. The patient sought care at our institution due to worsening symptoms.

Physical examination revealed abdominal distension with deep tenderness in the upper abdomen and mild percussion pain in the hepatic region. Vital signs were stable: temperature 36.4°C, pulse 71 beats/minute, respiratory rate 20 breaths/minute, and blood pressure 126/81 mmHg. No jaundice, hepatosplenomegaly.

Laboratory investigations showed normal complete blood count, liver and renal function tests. Tumor markers, including carcinoembryonic antigen (0.37 ng/ml), alpha-fetoprotein (3.79 ng/ml), and protein induced by vitamin K absence-II (PIVKA-II, 25 mAu/ml), were within normal ranges.

Enhanced CT scan of the abdomen revealed a well-demarcated, heterogeneously enhancing mass in liver segments 3 and 4, measuring approximately 6×5×4 cm with exophytic growth pattern ( Figures 1A–D ). The lesion demonstrated peripheral enhancement in the arterial phase with progressive central filling in the venous and delayed phases, initially raising suspicion for HCC or atypical hemangioma.

Chest CT incidentally identified a 14 mm part-solid nodule in the left upper lobe with a 2 mm solid component (CTR<0.5), classified as LU-RADS 4 ( Figure 1K ). Magnetic resonance imaging (MRI) with hepatocyte-specific contrast agent (gadoxetic acid) confirmed the liver mass with hypointensity on T1-weighted images ( Figure 1E ), mild hyperintensity on T2-weighted images( Figure 1F ), and heterogeneous enhancement with characteristic washout in the hepatobiliary phase ( Figures 1G–I ). The lesion demonstrated restricted diffusion on diffusion-weighted imaging, further supporting malignancy. Gastroscopy and colonoscopy were unremarkable.

The case was presented at our multidisciplinary tumor board, comprising hepatobiliary surgeons, thoracic surgeons, oncologists, radiologists, and pathologists. After thorough discussion, the consensus was that both lesions likely represented separate primary malignancies rather than metastatic disease. Given the patient’s symptomatic hepatic mass and its larger size, the team recommended a staged approach with initial hepatic resection followed by pulmonary resection after adequate recovery.

Primary hepatic leiomyosarcoma is one of the rarest primary liver malignancies, with fewer than 70 cases reported in the English literature (11). The challenge in diagnosis lies not only in its rarity but also in its nonspecific clinical and radiological features that often overlap with more common hepatic neoplasms (12).

In our case, the initial radiological impression suggested hepatocellular carcinoma, highlighting the limited specificity of imaging for this rare entity. Recent literature suggests that although certain radiological features may raise suspicion for PHL, including heterogeneous enhancement, central necrosis, and absence of typical HCC features (such as arterial hyperenhancement with portal/delayed phase washout), definitive diagnosis requires histopathological confirmation (13).

The importance of comprehensive immunohistochemical analysis cannot be overstated in the diagnosis of PHL. The tumor’s mesenchymal origin necessitates the demonstration of smooth muscle differentiation through positivity for SMA, desmin, and caldesmon, while excluding other sarcoma subtypes and metastatic disease (14). In our patient, the immunohistochemical profile was classic for leiomyosarcoma, with strong positivity for SMA, desmin, vimentin, and caldesmon, while negative for epithelial markers (cytokeratins), gastrointestinal stromal tumor markers (CD117, DOG-1), and other mesenchymal tumor markers (STAT6, SATB2).

Establishing the primary hepatic origin of leiomyosarcoma requires the exclusion of metastasis from other sites, particularly the gastrointestinal tract, retroperitoneum, and female genital tract. Our patient underwent comprehensive evaluations, including gastroscopy, colonoscopy, PET/CT, and gynecological examination, which excluded potential primary tumors elsewhere, supporting the diagnosis of PHL.

Complete surgical resection with negative margins remains the cornerstone of treatment for PHL, offering the best chance for long-term survival (15). The choice between open and laparoscopic approaches should be individualized based on tumor location, size, and relationship to vascular structures (16).

In our case, laparoscopic partial left hepatectomy was chosen due to the peripheral location of the tumor in segments 3 and 4, absence of major vascular involvement, and the surgeon’s expertise in minimally invasive liver surgery. The advantages of the laparoscopic approach include reduced postoperative pain, shorter hospital stay, and faster recovery, particularly relevant in our patient who required subsequent pulmonary surgery.

The surgical strategy for PHL should aim for R0 resection with a minimum margin of 1 cm when possible (17). While anatomical resection is generally preferred for HCC, non-anatomical parenchymal-sparing resection may be appropriate for PHL, particularly when located peripherally, as the tumor typically spreads by direct invasion rather than through portal venous dissemination (18). Our surgical approach aligned with these principles, achieving clear margins while preserving functional liver parenchyma.

The role of lymphadenectomy in PHL remains controversial due to limited data. Unlike HCC, where lymphatic spread is uncommon, sarcomas may metastasize via lymphatics, suggesting a potential benefit of regional lymphadenectomy (19). In our case, locoregional lymph nodes were sampled but showed no evidence of metastasis.

The occurrence of synchronous primary malignancies presents unique challenges in determining the optimal sequence and modalities of treatment. The decision-making process should consider the stage, potential aggressiveness, and symptomatology of each tumor, as well as the patient’s overall condition (20, 21).

In our case, the multidisciplinary team recommended addressing the hepatic tumor first, based on several considerations: (1) the hepatic tumor was larger and more symptomatic; (2) PHL generally has a more aggressive clinical course compared to early-stage lung adenocarcinoma; and (3) the pulmonary lesion was small with predominantly ground-glass appearance, suggesting indolent behavior.

This staged approach allowed adequate recovery between procedures and avoided the potential complications of simultaneous major surgeries. The successful outcome in our patient supports the value of this strategy, though it must be emphasized that treatment decisions for such rare dual malignancies should be individualized through multidisciplinary discussion.

The pathogenetic relationship between primary hepatic leiomyosarcoma and lung adenocarcinoma remains speculative due to the extreme rarity of this combination. Several theories might explain the occurrence of double primary malignancies:

In our patient, the absence of known risk factors for either malignancy (no smoking history, hepatitis, or family history of cancer) suggests either unidentified environmental exposures, subtle genetic predisposition, or simply a rare coincidence. Molecular profiling of both tumors might provide insights into potential common pathogenetic mechanisms, representing an area for future research. Although molecular profiling using next-generation sequencing of both tumors could potentially provide valuable insights into common pathogenetic mechanisms, this was not performed in our case due to technical and financial limitations. Future studies incorporating comprehensive molecular characterization would be beneficial in understanding the genetic basis of such rare synchronous malignancies.

The prognosis of PHL is generally poor, with reported 5-year survival rates ranging from 19-37% (8). Recent registry analyses from the Surveillance, Epidemiology, and End Results (SEER) database suggest that complete surgical resection remains the most significant prognostic factor, with potentially improved outcomes in the era of advanced surgical techniques and targeted therapies (22).Factors associated with poor outcomes include tumor size >5 cm, high-grade histology, presence of necrosis, and positive surgical margins (23). In our patient, although the tumor was relatively large (6 cm) with focal necrosis, complete resection with negative margins was achieved, potentially improving her prognosis.

For early-stage lung adenocarcinoma (stage IA), the prognosis is generally favorable, with 5-year survival rates exceeding 80-90% following complete resection (24). The predominantly lepidic and acinar patterns observed in our patient’s tumor are associated with better outcomes compared to solid or micropapillary patterns.

The optimal surveillance strategy for patients with dual primary malignancies is not well established. We have implemented a tailored follow-up protocol for our patient, including:

This intensive surveillance is designed to detect potential recurrence of either malignancy at an early, potentially treatable stage. The role of adjuvant therapy for either tumor in our patient remains uncertain given the complete resection and early-stage disease. Current evidence does not support routine adjuvant therapy for completely resected PHL (25) or stage IA lung adenocarcinoma (26). However, close monitoring for recurrence with consideration of systemic therapy at the first sign of disease progression represents a prudent approach.

Several limitations should be acknowledged in this case report. First, the relatively short follow-up period limits our ability to make definitive conclusions about long-term outcomes. Second, the patient’s refusal of adjuvant chemotherapy may impact disease-free survival, particularly for the hepatic leiomyosarcoma. Third, the lack of molecular profiling limits our understanding of potential genetic drivers and shared pathogenetic mechanisms between these two rare synchronous malignancies. Finally, as with all case reports, findings from a single patient may not be generalizable to the broader population of patients with similar presentations.

We acknowledge that immunohistochemical markers such as SMA, desmin, caldesmon, TTF-1, and Napsin A are not entirely specific to their respective tumor types. However, the divergent histological architecture, mutually exclusive marker expression, and discordant anatomical and clinical behavior of the two tumors argue strongly against a metastatic relationship. Although molecular profiling (e.g., NGS) could have provided additional confirmation, it was not performed due to financial and technical constraints. We recognize this as a limitation and propose that future studies of similar cases include genomic analysis to further delineate the origin of such rare synchronous tumors.